//! DRM/udev backend: runs srdwm as the real compositor on a bare TTY (no //! host session to nest under), unlike the `backend_winit`-based path in //! `lib.rs`. //! //! Scope: //! - Single primary GPU, but **every** connected connector on it: each //! becomes a [`UdevHead`] with its own scanout buffers, damage tracker //! and page-flip state, laid out left-to-right in the global coordinate //! space. Connectors are re-probed on hotplug (see `reprobe_outputs`); //! a second GPU is not supported. //! - Rendering is **software**, via smithay's `PixmanRenderer` compositing //! into plain KMS "dumb buffers" through the legacy (non-atomic) mode-set //! API (`set_crtc`/`page_flip`). This deliberately avoids the //! GBM/EGL/`DrmCompositor` pipeline real hardware-accelerated compositors //! (and smithay's own `anvil` example) use: that path needs a GPU with //! working KMS+3D driver support, which is not guaranteed in a low-spec //! machine's VM (QEMU's plainest virtual display devices only support //! dumb-buffer scanout). Dumb buffers work on essentially any DRM driver. //! - Session/seat handling is real, via `libseat` (VT-switch-safe device //! access, no root required if the seatd/logind + libseat setup is //! present) - not a raw `/dev/dri/cardN` open. //! - Input is real, via `libinput`, sharing the exact same precise //! keybinding matching and pointer/titlebar hit-testing code paths //! `handle_keyboard_key_event`/`handle_pointer_position`/ //! `handle_pointer_button` in `lib.rs` use for the nested winit backend. //! - Session pause/resume (VT switch away/back) stops/resumes rendering, //! but does not yet re-probe connectors on resume. use std::cell::RefCell; use std::collections::{HashMap, HashSet}; use std::os::fd::{AsFd, AsRawFd, BorrowedFd, OwnedFd}; use std::rc::Rc; use std::time::{Duration, Instant}; use smithay::backend::input::{ Axis, ButtonState as BackendButtonState, Event as InputEventTrait, InputEvent, PointerAxisEvent, PointerButtonEvent, PointerMotionEvent, }; use smithay::backend::libinput::{LibinputInputBackend, LibinputSessionInterface}; use smithay::backend::renderer::damage::OutputDamageTracker; use smithay::backend::renderer::element::memory::MemoryRenderBufferRenderElement; use smithay::backend::renderer::element::Kind; use smithay::backend::renderer::pixman::PixmanRenderer; use smithay::backend::renderer::{Bind, ImportDma}; use smithay::backend::session::{libseat::LibSeatSession, libseat::LibSeatSessionNotifier, Event as SessionEvent, Session}; use smithay::backend::udev::{self, UdevBackend, UdevEvent}; use smithay::desktop::{layer_map_for_output, PopupManager, Space}; use smithay::backend::input::AxisSource; use smithay::wayland::shell::wlr_layer::Layer; use smithay::input::pointer::AxisFrame; use smithay::input::SeatState; use smithay::output::{Mode as OutputMode, Output, PhysicalProperties, Subpixel}; use smithay::reexports::calloop::generic::{FdWrapper, Generic}; use smithay::reexports::calloop::{EventLoop, Interest, LoopHandle, Mode as CalloopMode, PostAction}; use smithay::reexports::drm::buffer::{Buffer as DrmBufferTrait, DrmFourcc}; use smithay::reexports::drm::control::{ connector, crtc, dumbbuffer::DumbBuffer, framebuffer, Device as ControlDevice, Event as DrmEvent, Mode as DrmMode, ModeTypeFlags, PageFlipFlags, }; use smithay::reexports::drm::Device as BasicDevice; use smithay::reexports::input::Libinput; use smithay::reexports::pixman::{FormatCode, Image}; use smithay::reexports::rustix; use smithay::reexports::wayland_server::backend::GlobalId; use smithay::reexports::wayland_server::{Client, Display, DisplayHandle, ListeningSocket}; use smithay::utils::{Logical, Physical, Point, Rectangle, Scale, Size, Transform}; use smithay::wayland::compositor::CompositorState; use smithay::wayland::dmabuf::DmabufState; use smithay::wayland::selection::data_device::DataDeviceState; use smithay::wayland::selection::primary_selection::PrimarySelectionState; use smithay::wayland::selection::wlr_data_control::DataControlState; use smithay::wayland::shell::xdg::decoration::XdgDecorationState; use smithay::wayland::shell::xdg::XdgShellState; use smithay::wayland::shm::ShmState; use smithay::wayland::xdg_activation::XdgActivationState; use srdwm_core::{Event as CoreEvent, WindowManager}; use srdwm_platform::{Platform, PlatformError, PlatformKind, Result as PlatformResult}; use crate::decoration; use crate::err; use crate::input::{handle_keyboard_key_event, handle_pointer_button, handle_pointer_position}; use crate::state::{ClientState, CompState}; /// A DRM device node, opened through the session (not a raw `File::open`) /// so access is properly gated by logind/seatd and revoked on VT switch. pub(crate) struct Card(OwnedFd); impl AsFd for Card { fn as_fd(&self) -> BorrowedFd<'_> { self.0.as_fd() } } impl BasicDevice for Card {} impl ControlDevice for Card {} pub(crate) struct DrmBuffer { dumb: DumbBuffer, fb: framebuffer::Handle, image: Image<'static, 'static>, } /// One connector+CRTC pair srdwm scans out to - i.e. one physical monitor. /// /// Each head owns its own scanout buffers, damage tracker and flip state, /// because monitors have independent resolutions and refresh cycles: a flip /// completing on one says nothing about the others. The *renderer* is not /// here but on [`UdevState`], since all heads on one GPU share it. pub(crate) struct UdevHead { pub(crate) crtc: crtc::Handle, /// Which connector this head drives - the key hotplug diffs against. pub(crate) connector: connector::Handle, pub(crate) output: Output, /// The `wl_output` global, kept so it can be destroyed when the monitor /// is unplugged; leaving it advertised would show clients a screen that /// no longer exists. pub(crate) global: GlobalId, pub(crate) damage_tracker: OutputDamageTracker, pub(crate) buffers: [DrmBuffer; 2], pub(crate) front: usize, /// A flip is in flight; the next frame for this head waits for the DRM /// page-flip event (matched by `crtc`) before starting. pub(crate) flip_pending: bool, /// Per-buffer-slot age passed to `damage_tracker.render_output`: how /// many *damage-producing* renders ago that exact buffer was last /// brought fully up to date. 0 means "never rendered, contents /// undefined" and forces a full redraw. This used to be hardcoded to 0 /// on every single call regardless - which, per /// `OutputDamageTracker::damage_output_internal`, forces the entire /// output geometry to be treated as damaged every time, so every frame /// was a full-screen software (pixman) recomposite plus a page-flip, /// nonstop, at whatever rate the event loop's 16ms dispatch timeout /// allowed - continuously, even with a fully idle desktop. That /// competes for the same single thread's CPU time as libinput event /// processing and is exactly what `client bug: event processing /// lagging behind` (logged for both the keyboard and the mouse) was /// reporting. With correct ages, a call that finds no real damage /// returns near-free (`damage_output_internal`'s own element/geometry /// comparison, no pixel work) and skips the flip entirely instead of /// always finding "damage". pub(crate) ages: [usize; 2], /// Origin of this head in the global coordinate space. pub(crate) location: Point, pub(crate) size: (i32, i32), } /// Everything the DRM/udev backend needs that the nested winit backend /// doesn't. Lives as a field on `CompState` (rather than a separate struct) /// because calloop callbacks registered against the event loop only ever /// get `&mut CompState` - see the module docs in `lib.rs` for why the /// protocol-handler state itself has to be backend-agnostic. pub(crate) struct UdevState { pub(crate) card: Rc, /// Shared by every head: one GPU, one software renderer. pub(crate) renderer: PixmanRenderer, pub(crate) heads: Vec, pub(crate) active: bool, /// Pointer position in the *global* space, so it can cross between /// monitors; clamped to the union of all head rectangles. pub(crate) pointer_pos: Point, } impl UdevState { /// Bounding box of every head, used to clamp pointer motion. fn bounds(&self) -> (f64, f64) { let w = self.heads.iter().map(|h| h.location.x + h.size.0).max().unwrap_or(0); let h = self.heads.iter().map(|h| h.location.y + h.size.1).max().unwrap_or(0); (w as f64, h as f64) } } impl CompState { /// Renders and (if there was damage) page-flips a new frame on every /// head that is ready for one. A head with a flip still in flight is /// skipped this pass and picked up when its page-flip event arrives, so /// monitors on different refresh rates each run at their own pace /// instead of the slowest one gating the rest. pub(crate) fn render_udev_frame(&mut self) { self.tick_animations(); self.tick_dirty_broadcasts(); let locked = self.lock.locked; let elapsed = self.start_time.elapsed(); // Drained before the `&mut self.udev` borrow below, so screencopy can // be serviced with the renderer that borrow owns. let mut captures = std::mem::take(&mut self.screencopy_pending); // Same reason: the cursor needs the renderer that borrow owns. let cursor_status = self.cursor_status.clone(); let cursor_buffers = self.cursor_buffers.clone(); // Border geometry is in global space, independent of which head // renders it, so it's gathered once here rather than per head. // Buffers are pre-built for the same reason as `cursor_buffers`: // Rendered per window, front-to-back (topmost first), each window's // content immediately followed by its decoration and border -- // fixes the same cross-window ordering bug documented in // `winit.rs`'s render loop: a background window's titlebar could // otherwise show through in front of the actually-focused window on // top of it, since decorations/borders used to be a single flat // layer drawn unconditionally above *every* window's content // regardless of real stacking order. `visible_windows_front_to_back` // is `WindowManager.order` reversed - not `visible_windows`, which // iterates the `windows` HashMap with no ordering guarantee - the // same "topmost first" convention `hit_test`/`window_at` use. // Fetched once here (`&mut self` fields, id_to_window/space lookups // happen per head below without needing `self` itself mutably) -- // see the per-head loop for why decoration/border buffers still get // looked up fresh per head (head-local `origin` translation). let ids: Vec = if locked { Vec::new() } else { self.wm.borrow().visible_windows_front_to_back().map(|w| w.id).collect() }; let focused = self.wm.borrow().focused_id(); let popup_targets = if locked { Vec::new() } else { crate::elements::popup_targets(self) }; // Which heads are eligible, and what each needs, gathered before the // mutable borrow of `self.udev`. Both early-outs below give the // `captures` taken above nowhere to go this pass - put them back // rather than silently dropping a client's pending screenshot // because a VT switch happened to be in progress at that instant. let Some(udev) = self.udev.as_ref() else { self.screencopy_pending.extend(captures); return; }; if !udev.active { self.screencopy_pending.extend(captures); return; } let ready: Vec<(usize, Output)> = udev .heads .iter() .enumerate() .filter(|(_, h)| !h.flip_pending) .map(|(i, h)| (i, h.output.clone())) .collect(); // Kept separately from `presented` below: layer-shell surfaces // (bars, docks) get their frame callback every pass regardless of // `has_damage`, unlike toplevel windows - see the callback loop at // the end of this function for why the two can't share one gate. let ready_outputs: Vec = ready.iter().map(|(_, o)| o.clone()).collect(); // Damage rects travel alongside each presented output so the // frame-callback loop below (after `udev` is no longer borrowed) // can notify only the windows that damage actually overlapped -- // see `windows_touched_by_damage`'s doc comment in elements.rs. let mut presented: Vec<(Output, Vec>)> = Vec::new(); for (index, output) in ready { let lock_surface = self.lock_surface_for(&output).cloned(); // Content/decoration elements are built per head: both need the // renderer, and geometry is translated into head-local space. let origin = self.udev.as_ref().map(|u| u.heads[index].location).unwrap_or_default(); let Some(udev) = self.udev.as_mut() else { return }; let head = &mut udev.heads[index]; let back = 1 - head.front; let mut custom_elements: Vec> = Vec::new(); if !locked { // Cursor first: `render_output` draws custom elements // front-to-back, so the earliest element is topmost. On a // bare TTY nothing else draws a pointer - see `cursor.rs`. let pointer_pos = udev.pointer_pos; let hsize = udev.heads[index].size; custom_elements.extend(crate::cursor::render_elements( &cursor_status, &cursor_buffers, &mut udev.renderer, pointer_pos, origin, hsize, )); // The right-click titlebar menu, if open - pushed right // after the cursor so it's still topmost over every window // but never hides the pointer itself (you need to see what // you're about to click). if let (Some(menu), Some(buffer)) = (self.context_menu.as_ref(), self.context_menu_buffer.as_ref()) { let pos = ((menu.pos.0 - origin.x) as f64, (menu.pos.1 - origin.y) as f64); match MemoryRenderBufferRenderElement::from_buffer(&mut udev.renderer, pos, buffer, None, None, None, Kind::Unspecified) { Ok(elem) => custom_elements.push(crate::elements::OverlayElement::Memory(elem)), Err(e) => log::warn!("udev: failed to import context menu buffer: {e}"), } } // Popups next: always above every window's own content, // matching this codebase's long-standing behavior from // before content moved into this same `custom_elements` // list (see below) - pushing them here, ahead of every // window and every layer-shell surface, is what keeps that // true now that "above everything in `self.space`" is no // longer a free property of a separate tier. custom_elements.extend(crate::elements::popup_render_elements(&popup_targets, &mut udev.renderer, (origin.x, origin.y))); // The bar/dock/launcher (`Layer::Top`/`Overlay`): rendered // ourselves via `output_layer_elements`, not through // `render_output`'s automatic inclusion of `self.space` + // `layer_map_for_output` - see this function's own call // site further down for why content had to stop flowing // through that convenience wrapper at all (per-window // opacity), which took layer-shell inclusion down with it as // a side effect. Skipped entirely - not just covered - for // a fullscreen window: `we should not see the bar at all`, // and unmapping it (`gtk_shell`) or covering it are two // different guarantees. `ids` is already front-to-back, so // checking every id for `fullscreen` here (rather than just // the frontmost) covers a fullscreen window stacked behind // an always-on-top one too. let hide_top_layers = ids.iter().any(|&id| self.wm.borrow().window(id).is_some_and(|w| w.fullscreen)); if !hide_top_layers { custom_elements.extend(crate::elements::output_layer_elements( &mut udev.renderer, &output, (origin.x, origin.y), |layer| matches!(layer, Layer::Top | Layer::Overlay), )); } // Windows stacked in front of whichever one border/ // decoration is being built right now - `ids` is already // front-to-back, so this only ever needs appending to, not // recomputing. A window's own *content*, pushed inside this // same loop below, needs no separate occlusion test: it // draws in the same front-to-back push order as everything // else here, so ordinary painter's-algorithm draw order // already occludes it correctly (this is exactly why content // used to occlude correctly via `self.space`'s own order, // before it had to move into this list for per-window // opacity to be possible at all). The border strips and // titlebar bitmap are different: outside `geometry`, drawn // via a bitmap that isn't itself window-shaped, so they // still need `occluders`' explicit clip against whichever // window is stacked in front. let mut occluders: Vec = Vec::with_capacity(ids.len()); for &id in &ids { let Some(w) = self.wm.borrow().window(id).cloned() else { continue }; // `w.geometry` is the animation's *target*, not // necessarily where the window is actually drawn this // frame - during a maximize/fullscreen/open-slide tween, // `sync_geometry` already renders the window's own // content at `window_anims`' interpolated rect (see its // doc comment), but this loop used to read `w.geometry` // straight from the model regardless, so the border and // titlebar sat at the final rect while the content they // were supposed to outline slid past underneath them -- // reported live as the border "not flush" with the // window during any animated transition. Every use of // this window's geometry below (titlebar/border // placement *and* the occlusion test against later // windows) has to agree with what `sync_geometry` mapped // the content to, or they drift apart again. let geom = self.window_anims.get(&id).map(crate::state::WindowAnim::current_rect).unwrap_or(w.geometry); // Drawn first among this window's own decoration, and // positioned from the same animated `geom` as everything // else here - not `w.geometry` - for the identical // reason: a shadow that stayed at the pre-tween rect // while the window slid past it would look exactly as // detached as the border did before that fix. Not // fragment-clipped against `occluders` like the titlebar/ // border below: at `SHADOW_MAX_ALPHA`'s low opacity, a // shadow bleeding slightly onto a window stacked in front // of this one reads as a soft edge, not the hard-line // bleed-through that made the titlebar/border need it. if let Some(shadow) = self.shadow_buffers.get(&id) { let rect = decoration::shadow_rect(geom); let pos = ((rect.x - origin.x) as f64, (rect.y - origin.y) as f64); match MemoryRenderBufferRenderElement::from_buffer(&mut udev.renderer, pos, shadow, None, None, None, Kind::Unspecified) { Ok(elem) => custom_elements.push(crate::elements::OverlayElement::Memory(elem)), Err(e) => log::warn!("udev: failed to import shadow buffer: {e}"), } } if let Some(deco) = self.decorations.get(&id) { // Fragment-clipped, same as the three solid border // strips below - an *all-or-nothing* version of // this (skip only once fully covered) was tried // first and reported live as still showing "the // behind window's bar": a titlebar only *partially* // covered - the common case for cascaded/ // overlapping windows - drew in full regardless, // bleeding through the covered part. `from_buffer`'s // `src` parameter crops the bitmap itself, so each // visible fragment can come from the matching // sub-rect of the source image rather than the // whole thing. let titlebar_rect = srdwm_core::Rect::new(geom.x, geom.y, geom.width, srdwm_core::TITLEBAR_HEIGHT); for fragment in crate::elements::visible_border_fragments(titlebar_rect, &occluders) { let pos = ((fragment.x - origin.x) as f64, (fragment.y - origin.y) as f64); let src = Rectangle::new( Point::from(((fragment.x - titlebar_rect.x) as f64, (fragment.y - titlebar_rect.y) as f64)), Size::from((fragment.width as f64, fragment.height as f64)), ); match MemoryRenderBufferRenderElement::from_buffer(&mut udev.renderer, pos, deco, None, Some(src), None, Kind::Unspecified) { Ok(elem) => custom_elements.push(crate::elements::OverlayElement::Memory(elem)), Err(e) => log::warn!("udev: failed to import titlebar buffer: {e}"), } } } // Border strips sit entirely outside this window's own // `geometry` (see `decoration::border_strips`), so they // never overlap its own decoration/content - draw // order against those doesn't matter here, only against // other windows', which iterating `ids` in stacking // order already gets right *for windows also drawn via // this same custom_elements loop* - but not against // any window's own *content*, which is why `occluders` // below is still needed even with that ordering. if w.border_width > 0 { let color = crate::state::effective_border_color(w.border_color, focused == Some(id)); let strips = decoration::border_strips(geom, w.border_width); // Strip 0 (top) rounded to match the titlebar under // it - see `render_border_top`'s doc comment - so // it's a cached bitmap (rebuilt only in // `redraw_decoration_buffer`, same as the titlebar // itself), not rasterized fresh here every frame. // Not fragment-clipped like the other three strips // below - cropping a bitmap's source rect per // fragment is real extra work for a strip that's // only `border_width` pixels tall to begin with, so // this only handles the all-or-nothing case: skip // entirely once *fully* covered, accept a small // residual bleed while only partially covered. if strips[0].width > 0 && strips[0].height > 0 && !strips[0].subtract_all(&occluders).is_empty() { if let Some(buffer) = self.border_top_decorations.get(&id) { let pos = ((strips[0].x - origin.x) as f64, (strips[0].y - origin.y) as f64); match MemoryRenderBufferRenderElement::from_buffer(&mut udev.renderer, pos, buffer, None, None, None, Kind::Unspecified) { Ok(elem) => custom_elements.push(crate::elements::OverlayElement::Memory(elem)), Err(e) => log::warn!("udev: failed to import top border buffer: {e}"), } } } // The other three strips are persistent // `SolidColorBuffer`s updated in place, not rebuilt // with a fresh `Id` every frame - see // `elements::border_side_render_element`'s doc // comment for why that distinction is load-bearing // for damage tracking, not cosmetic. Each strip is // further split into whatever fragments remain // visible after subtracting `occluders`, since a // whole unclipped strip is exactly the bug fixed // here. let pool = self.border_side_buffers.entry(id).or_default(); let mut buf_index = 0; for strip in &strips[1..] { if strip.width == 0 || strip.height == 0 { continue; } for fragment in crate::elements::visible_border_fragments(*strip, &occluders) { let buf = crate::elements::border_fragment_buffer(pool, buf_index); buf_index += 1; custom_elements.push(crate::elements::OverlayElement::Solid(crate::elements::border_side_render_element(buf, fragment, color, (origin.x, origin.y)))); } } } // The window's own content, at its own `opacity` -- // this, not decoration, is the entire reason content // moved into this loop at all (see the doc comment on // the popup push above). Positioned the same way // `sync_geometry` maps it into `self.space` (band added // for a decorated window's titlebar reservation), so // switching rendering paths doesn't also shift content // relative to where clicks still land (hit-testing is // untouched, still `w.geometry`/`self.space`-based). if let Some(dwindow) = self.id_to_window.get(&id) { if let Some(surface) = crate::elements::window_wl_surface(dwindow) { let band = if w.decorated { srdwm_core::TITLEBAR_HEIGHT as i32 } else { 0 }; let pos = (geom.x - origin.x, geom.y + band - origin.y); custom_elements.extend(crate::elements::surface_content_elements(&mut udev.renderer, &surface, pos, w.opacity)); } } occluders.push(geom); } // Background/bottom layer-shell (wallpaper engines) last -- // bottommost, matching smithay's own `space_render_elements` // ordering, which this whole custom loop now replaces. custom_elements.extend(crate::elements::output_layer_elements( &mut udev.renderer, &output, (origin.x, origin.y), |layer| matches!(layer, Layer::Background | Layer::Bottom), )); } let lock_elements = if locked { crate::lock::lock_render_elements(lock_surface.as_ref(), &mut udev.renderer) } else { Vec::new() }; let head = &mut udev.heads[index]; let mut framebuffer = match udev.renderer.bind(&mut head.buffers[back].image) { Ok(fb) => fb, Err(e) => { log::error!("udev: pixman bind failed: {e}"); continue; } }; // Locked heads draw the lock surface over opaque black and // nothing else; unlocked heads draw the normal scene. let result = if locked { head.damage_tracker .render_output(&mut udev.renderer, &mut framebuffer, 0, &lock_elements, [0.0, 0.0, 0.0, 1.0]) .map(|r| (r.damage.is_some(), Vec::new())) .map_err(|e| e.to_string()) } else { // Not `smithay::desktop::space::render_output`: that // convenience wrapper draws `self.space`'s window content at // one `alpha` for the whole frame and pulls every // layer-shell surface in unconditionally, neither of which // leaves room for per-window opacity or hiding the bar/dock // during fullscreen. `custom_elements` above already carries // everything that wrapper would have built - window // content (`surface_content_elements`, one call per window, // each with its own `w.opacity`) and layer-shell surfaces // (`output_layer_elements`, split Top/Overlay above content // and Background/Bottom below it) - assembled by hand in // the correct front-to-back order instead. `self.space` // itself is untouched and still authoritative for // hit-testing/stacking bookkeeping (`sync_geometry`'s // `map_element` calls); only the *render* path stopped // reading from it. head.damage_tracker .render_output(&mut udev.renderer, &mut framebuffer, head.ages[back], &custom_elements, [0.05, 0.05, 0.08, 1.0]) .map(|r| (r.damage.is_some(), r.damage.cloned().unwrap_or_default())) // Both arms reduce to "was there damage" plus the damage // rects themselves; the two error types differ, so they are // flattened to a message here. .map_err(|e| e.to_string()) }; if !locked { // Only this head's own captures: `captures` holds requests // for every output, and each must be read back from the // framebuffer it was actually requested against, not // whichever head happens to render first in this loop (a // multi-monitor capture would otherwise silently read the // wrong screen). Whatever doesn't match `output` stays in // `captures` for a later head this same pass. let (mine, rest): (Vec<_>, Vec<_>) = captures.into_iter().partition(|c| c.output == output); captures = rest; crate::screencopy::service_pending(mine, &mut udev.renderer, &framebuffer); } drop(framebuffer); let (has_damage, damage_rects) = match result { Ok(v) => v, Err(e) => { log::error!("udev: render_output failed: {e}"); continue; } }; if has_damage { let head = &mut udev.heads[index]; if let Err(e) = head.copy_and_flip(&udev.card, back) { log::error!("udev: page flip failed: {e}"); continue; } // This buffer is now fully up to date. It won't be rendered // into again until the *other* slot has also been presented // once (strict two-buffer alternation), so by then it will // be exactly 2 damage-producing renders stale - matching // `damage_tracker`'s own history, which only advances on // calls that actually found damage (see `ages`' doc // comment). head.ages[back] = 2; // Only a head that actually presented a new frame should // tell its windows they may render their next one - this // used to run unconditionally for every "ready" head (i.e. // every head not already mid-flip) on every single call to // this function, which is every ~16ms regardless of // activity. A client that renders on the standard // wait-for-frame-callback pattern (which is most of // them - confirmed live: wezterm-gui pinned at 140%+ CPU // sitting on a fully idle, unchanged terminal) had no // reason not to redraw at whatever rate this loop cycled, // forever, since it kept getting told a new frame was // wanted whether or not the screen had changed at all. presented.push((output, damage_rects)); } } // Frame callbacks + lock confirmation, once the `udev` borrow is done. for (output, damage_rects) in presented { if locked { let surface = self.lock_surface_for(&output).cloned(); crate::lock::send_lock_frame(surface.as_ref(), &output, elapsed); self.confirm_lock_if_presented(&output); } else { let out = output.clone(); let scale = Scale::from(out.current_scale().fractional_scale()); for w in crate::elements::windows_touched_by_damage(&self.space, &damage_rects, scale) { w.send_frame(&out, elapsed, None, |_, _| Some(out.clone())); } } } // Deliberately unconditional - not folded into the `presented` // loop above, and not gated on any head having had damage this // tick at all. The whole point of `always_notify` is covering the // case where the output has *no* damage whatsoever (a fully idle // desktop, cursor not moving) but the focused/hovered window still // has a pending callback it needs answered to unblock an input- // driven redraw - GTK's frame-clock model (Firefox's Wayland // vsync source included) paces every repaint through that // callback, even the first one after being idle, with no "just // commit immediately" fallback. Nesting this inside the `presented` // loop (the first version of this fix) meant it only ever ran on a // tick that already had damage from something else happening -- // i.e. never in the exact scenario it exists for. Reported live as // clicks in Firefox still doing nothing at all, not just // intermittently, after the first version of this fix. if !locked { let pointer_pos = self.udev.as_ref().map(|u| u.pointer_pos).unwrap_or_default(); let wm = self.wm.borrow(); let always_notify = [wm.focused_id(), wm.window_at(pointer_pos.x as i32, pointer_pos.y as i32)]; drop(wm); let outputs: Vec = self.outputs.iter().map(|e| e.output.clone()).collect(); for w in always_notify.into_iter().flatten().filter_map(|id| self.id_to_window.get(&id)) { for out in &outputs { w.send_frame(out, elapsed, None, |_, _| Some(out.clone())); } } } // Layer-shell surfaces (bars, docks, launchers) get their frame // callback on every pass, unconditionally - NOT folded into the // `presented`/`has_damage` gate above. // // That gate exists because most toplevel clients redraw on the // standard wait-for-callback loop regardless of whether their own // content changed (confirmed live: wezterm-gui pinned at 140%+ CPU // on a fully idle terminal when it got a callback every ~16ms // whether or not the screen had changed). Gating toplevel callbacks // on real output damage fixed that. // // Applying the same gate to layer surfaces creates a real deadlock // instead: many (GTK4/AGS among them) drive their *entire* repaint // loop off frame callbacks with no independent timer fallback -- // paint once, request a callback, wait. If nothing ELSE on the // desktop ever produces damage again (a static terminal, no other // animation), that callback never arrives, so the surface can never // draw its next frame, which means it can never produce damage, // which means it never gets a callback - permanently frozen after // exactly one frame. Confirmed live: AGS and waybar both hung this // way, one frame in, with `wl_surface.frame` requests that were // never answered (see docs/PANEL_SUPPORT_TODO.md). // // Splitting the gate is safe rather than reintroducing the wezterm // bug: there are at most a handful of layer surfaces on a real // desktop (a bar, maybe a dock/launcher), their content is cheap to // redraw even when done needlessly, and periodic UI chrome (a // clock, a resource graph) is exactly the case frame callbacks // exist to pace - unlike a full toplevel window, whose redraw cost // is what made the unconditional case expensive in the first place. if !locked { for output in &ready_outputs { for layer in layer_map_for_output(output).layers() { layer.send_frame(output, elapsed, None, |_, _| Some(output.clone())); } } } if locked { crate::screencopy::fail_pending(captures); } else if !captures.is_empty() { // Left over because their target head wasn't in `ready` this // pass (e.g. mid-page-flip). Put back rather than dropped: this // function runs again on the next poll tick (or the page-flip // completion that made the head ready), so the capture gets // another chance instead of silently vanishing - which is what // made `grim` hang waiting on a `ready`/`failed` that would // otherwise never come (see docs/PANEL_SUPPORT_TODO.md, P1). self.screencopy_pending.extend(captures); } } /// Sets a connector's DPMS mode via the generic KMS "DPMS" property -- /// there is no dedicated legacy-API call for this in `drm-rs`, only the /// same `get_properties`/`set_property` pair every other connector /// property goes through, so the property has to be found by name each /// time rather than through some `Dpms` -specific method. `None` if the /// `wl_output` doesn't resolve to a live head, or the connector has no /// "DPMS" property at all (rare on real hardware, but virtual/headless /// outputs may not expose one) - either way maps to `zwlr_output_power_v1`'s /// `failed` event, matching what the protocol asks for when the mode /// can't be honoured. pub(crate) fn set_output_power(&self, wl_output: &smithay::reexports::wayland_server::protocol::wl_output::WlOutput, on: bool) -> Option<()> { // Raw KMS UAPI values for the "DPMS" connector property // (`DRM_MODE_DPMS_ON`/`_OFF` in `drm_sys`/the kernel's // `drm_mode.h`) - not worth a whole extra dependency on `drm-sys` // just for two constants that have been stable since DPMS was // added to the DRM UAPI. const DRM_MODE_DPMS_ON: u64 = 0; const DRM_MODE_DPMS_OFF: u64 = 3; let target = self.output_for_wl(wl_output)?.output.clone(); let udev = self.udev.as_ref()?; let head = udev.heads.iter().find(|h| h.output == target)?; let props = udev.card.get_properties(head.connector).ok()?; let dpms_prop = props.as_props_and_values().0.iter().copied().find(|&handle| udev.card.get_property(handle).is_ok_and(|info| info.name().to_str() == Ok("DPMS")))?; let mode = if on { DRM_MODE_DPMS_ON } else { DRM_MODE_DPMS_OFF }; udev.card.set_property(head.connector, dpms_prop, mode).ok() } /// The CRTC's gamma ramp length, in elements per channel - what /// `zwlr_gamma_control_v1.gamma_size` reports so a client knows how /// large a table `set_gamma` expects. `None` if the output doesn't /// resolve to a live head, or the CRTC reports a zero-length ramp /// (no gamma hardware, common on virtual/headless outputs). pub(crate) fn gamma_ramp_size(&self, wl_output: &smithay::reexports::wayland_server::protocol::wl_output::WlOutput) -> Option { let target = self.output_for_wl(wl_output)?.output.clone(); let udev = self.udev.as_ref()?; let head = udev.heads.iter().find(|h| h.output == target)?; let len = udev.card.get_crtc(head.crtc).ok()?.gamma_length(); (len > 0).then_some(len) } /// Reads a client-supplied gamma table (`zwlr_gamma_control_v1. /// set_gamma`'s `fd`: a memory-mapped blob of `gamma_size` `u16`s per /// channel, red then green then blue, per the protocol) and applies it /// to the CRTC. `None` on any failure - output/head not found, the /// blob is the wrong size, or the DRM `set_gamma` call itself fails -- /// which the caller maps to `zwlr_gamma_control_v1.failed`, exactly /// what the protocol specifies for "setting the gamma tables failed". pub(crate) fn set_gamma_ramp(&self, wl_output: &smithay::reexports::wayland_server::protocol::wl_output::WlOutput, fd: std::os::fd::OwnedFd) -> Option<()> { let target = self.output_for_wl(wl_output)?.output.clone(); let udev = self.udev.as_ref()?; let head = udev.heads.iter().find(|h| h.output == target)?; let size = udev.card.get_crtc(head.crtc).ok()?.gamma_length() as usize; if size == 0 { return None; } // Three channels, two bytes (one native-endian u16) per element -- // client and compositor are always the same machine, so there is // no cross-endianness concern to handle here, unlike an over-the- // wire protocol value. let expected_bytes = size * 3 * 2; // SAFETY: the fd is a client-supplied shared-memory blob, mapped // read-only for the duration of this call and never touched again // afterwards - the same trust boundary `wl_shm` buffers already // cross for every window's actual pixel content elsewhere in this // codebase. let map = unsafe { memmap2::MmapOptions::new().map(&fd) }.ok()?; if map.len() < expected_bytes { return None; } let read_channel = |offset: usize| -> Vec { map[offset..offset + size * 2].chunks_exact(2).map(|b| u16::from_ne_bytes([b[0], b[1]])).collect() }; let red = read_channel(0); let green = read_channel(size * 2); let blue = read_channel(size * 4); udev.card.set_gamma(head.crtc, &red, &green, &blue).ok() } } impl CompState { /// Re-probes connectors after a hotplug and reconciles the head list. /// /// Connectors that vanished have their head torn down (global removed, /// output unmapped, DRM buffers freed); newly connected ones are brought /// up exactly as they would have been at startup. Every head is then /// repositioned left-to-right, because removing a monitor shifts the /// ones after it. pub(crate) fn reprobe_outputs(&mut self) { let Some(udev) = self.udev.as_ref() else { return }; let card = udev.card.clone(); let probes = match probe_connected(&card) { Ok(p) => p, Err(e) => { log::warn!("udev: hotplug re-probe failed: {e}"); return; } }; let present: Vec = probes.iter().map(|p| p.connector).collect(); let existing: Vec = udev.heads.iter().map(|h| h.connector).collect(); let gone: Vec = existing.iter().copied().filter(|c| !present.contains(c)).collect(); let added: Vec = probes .iter() .enumerate() .filter(|(_, p)| !existing.contains(&p.connector)) .map(|(i, _)| i) .collect(); if gone.is_empty() && added.is_empty() { return; // a "changed" event that didn't change the connector set } log::info!("udev: hotplug - {} output(s) removed, {} added", gone.len(), added.len()); // ---- removals ---- for connector in &gone { let Some(udev) = self.udev.as_mut() else { return }; let Some(index) = udev.heads.iter().position(|h| h.connector == *connector) else { continue }; let head = udev.heads.remove(index); log::info!("udev: output {} disconnected", head.output.name()); self.dh.remove_global::(head.global.clone()); self.space.unmap_output(&head.output); self.outputs.retain(|e| e.output != head.output); // A lock surface for a monitor that no longer exists would keep // `confirm_lock_if_presented` waiting forever otherwise. self.lock.surfaces.remove(&head.output.name()); self.lock.presented.remove(&head.output.name()); head.release(&card); self.pending.borrow_mut().push(CoreEvent::MonitorRemoved(index as u32)); } // ---- additions ---- for i in added { let probe = &probes[i]; let used: Vec = self.udev.as_ref().map(|u| u.heads.iter().map(|h| h.crtc).collect()).unwrap_or_default(); let Some(crtc) = pick_crtc(&card, probe, &used) else { log::warn!("udev: no free CRTC for newly connected {}; not driving it", probe.name); continue; }; // Placed at 0 for now; the re-layout below assigns real offsets. match bring_up_head(&card, &self.dh.clone(), probe, crtc, 0) { Ok((head, entry)) => { log::info!("udev: output {} connected ({}x{})", probe.name, head.size.0, head.size.1); let monitor_id = self.outputs.len() as u32; let geometry = srdwm_core::Rect::new(0, 0, head.size.0 as u32, head.size.1 as u32); if let Some(udev) = self.udev.as_mut() { udev.heads.push(head); } self.outputs.push(entry); self.pending .borrow_mut() .push(CoreEvent::MonitorAdded(srdwm_core::Monitor::new(monitor_id, probe.name.clone(), geometry))); } Err(e) => log::warn!("udev: failed to bring up {}: {e}", probe.name), } } self.relayout_outputs(); } /// Repositions every head left-to-right and republishes the new /// positions to the output globals, the `Space`, and the layer maps. fn relayout_outputs(&mut self) { let Some(udev) = self.udev.as_mut() else { return }; let mut x = 0; let mut placed: Vec<(Output, Point)> = Vec::new(); for head in &mut udev.heads { head.location = (x, 0).into(); head.output.change_current_state(None, None, None, Some((x, 0).into())); placed.push((head.output.clone(), head.location)); x += head.size.0; } for (output, location) in placed { if let Some(entry) = self.outputs.iter_mut().find(|e| e.output == output) { entry.location = location; } self.space.map_output(&output, (location.x, location.y)); // Bars are anchored to their output, so their geometry has to be // recomputed against the moved output rectangle. layer_map_for_output(&output).arrange(); } } } impl UdevHead { /// Frees the DRM resources this head owns. Dropping the Rust structs /// alone would leak the kernel-side framebuffers and dumb buffers, /// which matters when a monitor is plugged and unplugged repeatedly. fn release(self, card: &Card) { for buffer in self.buffers { if let Err(e) = card.destroy_framebuffer(buffer.fb) { log::warn!("udev: destroy_framebuffer failed: {e}"); } if let Err(e) = card.destroy_dumb_buffer(buffer.dumb) { log::warn!("udev: destroy_dumb_buffer failed: {e}"); } } } /// Copies the just-rendered pixman image into buffer `back`'s dumb /// buffer (software rendering writes into its own owned image, not the /// scanout memory directly, to avoid tying that image's lifetime to an /// mmap - see this module's docs) and flips to it. fn copy_and_flip(&mut self, card: &Card, back: usize) -> std::io::Result<()> { let (src_stride, height) = (self.buffers[back].image.stride(), self.buffers[back].image.height()); let byte_len = src_stride * height; // SAFETY: `image` owns this memory and outlives the byte slice we // construct from it here; we only read, and only for the duration // of this call. let src: &[u8] = unsafe { std::slice::from_raw_parts(self.buffers[back].image.data() as *const u8, byte_len) }; // The dumb buffer's pitch is whatever the kernel driver actually // allocated, which the DRM API does not guarantee equals pixman's // own `src_stride` (drivers are free to pad each row for // alignment). This used to be a single flat `copy_from_slice` sized // off `src_stride` alone; on any driver that pads, that copies each // source row into the wrong offset in the destination, shearing the // image diagonally by one row per `dst_stride - src_stride` bytes of // padding. Copying row by row, each clamped to the narrower of the // two strides, is correct regardless of whether the strides happen // to match. let dst_stride = self.buffers[back].dumb.pitch() as usize; { let mut mapping = card.map_dumb_buffer(&mut self.buffers[back].dumb)?; let dst = mapping.as_mut(); let row_len = src_stride.min(dst_stride); for row in 0..height { let s = row * src_stride; let d = row * dst_stride; if s + row_len > src.len() || d + row_len > dst.len() { break; } dst[d..d + row_len].copy_from_slice(&src[s..s + row_len]); } } card.page_flip(self.crtc, self.buffers[back].fb, PageFlipFlags::EVENT, None)?; self.flip_pending = true; Ok(()) } } pub struct UdevPlatform { event_loop: EventLoop<'static, CompState>, display: Display, state: CompState, listener: ListeningSocket, clients: Vec, pending: Rc>>, ipc: Option, } impl UdevPlatform { pub fn connect(wm: Rc>, bound_keys: &[String], repeat_keys: &[String]) -> PlatformResult { let event_loop: EventLoop<'static, CompState> = EventLoop::try_new().map_err(err)?; let (session, notifier) = LibSeatSession::new().map_err(err)?; let seat_name = session.seat(); let gpu_path = udev::primary_gpu(&seat_name) .ok() .flatten() .unwrap_or_else(|| std::path::PathBuf::from("/dev/dri/card0")); log::info!("udev: using {} as primary GPU", gpu_path.display()); let mut session_for_open = session.clone(); let fd = session_for_open .open(&gpu_path, rustix::fs::OFlags::RDWR | rustix::fs::OFlags::CLOEXEC) .map_err(err)?; let card = Rc::new(Card(fd)); // Every connected connector becomes a head, laid out left-to-right. let connected = probe_connected(&card)?; log::info!("udev: {} connected output(s)", connected.len()); let renderer = PixmanRenderer::new().map_err(err)?; let dh = Display::::new().map_err(err)?; let display_handle = dh.handle(); // `zwp_linux_dmabuf_v1` - see `protocols.rs`'s `DmabufHandler` for // why `PixmanRenderer`, a pure software renderer, can still import // these (mmap, not GPU). `create_global` (v3) rather than the v4 // `..._with_default_feedback` variant: the latter needs a // `main_device` `dev_t` to steer multi-GPU clients toward the // right render node, which is a real gap worth closing later but // not required for a single-GPU client to allocate and hand over a // Linear-modifier buffer, which is all this backend can use anyway. let mut dmabuf_state = DmabufState::new(); dmabuf_state.create_global::(&display_handle, renderer.dmabuf_formats()); let mut heads: Vec = Vec::new(); let mut output_entries: Vec = Vec::new(); let mut used_crtcs: Vec = Vec::new(); let mut x_offset = 0; for probe in &connected { let Some(crtc) = pick_crtc(&card, probe, &used_crtcs) else { log::warn!("udev: no free CRTC left for connector {}; not driving it", probe.name); continue; }; let (head, entry) = bring_up_head(&card, &display_handle, probe, crtc, x_offset)?; log::info!("udev: head {}: {} {}x{} at x={x_offset}", heads.len(), probe.name, head.size.0, head.size.1); used_crtcs.push(crtc); x_offset += head.size.0; heads.push(head); output_entries.push(entry); } let Some(first) = heads.first() else { return Err(PlatformError::Other("udev: no usable outputs".into())); }; // Pointer starts centred on the first head. let (width, height) = first.size; // xdg-output - see the matching comment in `lib.rs`'s // `WaylandPlatform::connect` for why this isn't optional. smithay::wayland::output::OutputManagerState::new_with_xdg_output::(&display_handle); let compositor_state = CompositorState::new::(&display_handle); let xdg_shell_state = XdgShellState::new::(&display_handle); let xdg_decoration_state = XdgDecorationState::new::(&display_handle); let shm_state = ShmState::new::(&display_handle, Vec::new()); // Selection (clipboard) protocols - see the matching block in // `lib.rs`'s `WaylandPlatform::connect` for the ordering constraint. let primary_selection_state = PrimarySelectionState::new::(&display_handle); let data_control_state = DataControlState::new::(&display_handle, Some(&primary_selection_state), |_| true); let mut seat_state = SeatState::new(); let mut seat = seat_state.new_wl_seat(&display_handle, "seat0"); let system_xkb = crate::xkb_config::read(); let xkb_config = smithay::input::keyboard::XkbConfig { rules: "", model: system_xkb.model.as_deref().unwrap_or(""), layout: system_xkb.layout.as_deref().unwrap_or(""), variant: system_xkb.variant.as_deref().unwrap_or(""), options: system_xkb.options.clone(), }; // 600ms delay, not 200 - see `state.rs`'s `REPEAT_DELAY` doc // comment for why. seat.add_keyboard(xkb_config, 600, 25).map_err(err)?; seat.add_pointer(); // Each output occupies its own slice of the global space, so a // window's coordinates say which monitor it is on. let mut space = Space::default(); for entry in &output_entries { space.map_output(&entry.output, (entry.location.x, entry.location.y)); } let pending = Rc::new(RefCell::new(Vec::new())); let udev_state = UdevState { card: card.clone(), renderer, heads, active: true, pointer_pos: (width as f64 / 2.0, height as f64 / 2.0).into(), }; let state = CompState { compositor_state, xdg_shell_state, _xdg_decoration_state: xdg_decoration_state, shm_state, dmabuf_state, xdg_activation_state: XdgActivationState::new::(&display_handle), _text_input_manager_state: smithay::wayland::text_input::TextInputManagerState::new::(&display_handle), _input_method_manager_state: smithay::wayland::input_method::InputMethodManagerState::new::(&display_handle, |_client| true), _gtk_shell_state: crate::gtk_shell::GtkShellState::new::(&display_handle), seat_state, seat, space, popups: PopupManager::default(), outputs: output_entries, layer_shell_state: smithay::wayland::shell::wlr_layer::WlrLayerShellState::new::(&display_handle), dh: display_handle.clone(), data_device_state: DataDeviceState::new::(&display_handle), primary_selection_state, data_control_state, session_lock_state: smithay::wayland::session_lock::SessionLockManagerState::new::( &display_handle, |_| true, ), _screencopy_state: crate::screencopy::ScreencopyState::new::(&display_handle), screencopy_pending: Vec::new(), _foreign_toplevel_state: crate::foreign_toplevel::ForeignToplevelState::new::(&display_handle), foreign_toplevel_managers: Vec::new(), foreign_toplevel_handles: HashMap::new(), _workspace_state: crate::workspace::WorkspaceManagerState::new::(&display_handle), _output_power_state: Some(crate::output_power::OutputPowerManagerState::new::(&display_handle)), _gamma_control_state: Some(crate::gamma_control::GammaControlManagerState::new::(&display_handle)), _output_management_state: crate::output_management::OutputManagementState::new::(&display_handle), output_managers: Vec::new(), output_heads: HashMap::new(), output_modes: HashMap::new(), output_serial: 0, last_broadcast_outputs: Vec::new(), workspace_managers: Vec::new(), workspace_groups: Vec::new(), workspace_handles: HashMap::new(), _viewporter_state: smithay::wayland::viewporter::ViewporterState::new::(&display_handle), _fractional_scale_state: smithay::wayland::fractional_scale::FractionalScaleManagerState::new::(&display_handle), _cursor_shape_state: smithay::wayland::cursor_shape::CursorShapeManagerState::new::(&display_handle), idle_notifier_state: smithay::wayland::idle_notify::IdleNotifierState::new(&display_handle, event_loop.handle()), _idle_inhibit_manager_state: smithay::wayland::idle_inhibit::IdleInhibitManagerState::new::(&display_handle), idle_inhibiting_surfaces: Vec::new(), last_idle_notify: None, window_anims: HashMap::new(), last_broadcast_flags: HashMap::new(), last_broadcast_workspace: None, lock: Default::default(), cursor_status: smithay::input::pointer::CursorImageStatus::default_named(), cursor_buffers: crate::cursor::make_buffers(), last_titlebar_click: None, context_menu: None, context_menu_buffer: None, wm: wm.clone(), surface_to_id: HashMap::new(), id_to_window: HashMap::new(), dead_layer_surfaces: HashSet::new(), decorations: HashMap::new(), border_top_decorations: HashMap::new(), shadow_buffers: HashMap::new(), border_side_buffers: HashMap::new(), last_synced_size: HashMap::new(), pending: pending.clone(), bound_keys: Rc::new(bound_keys.iter().cloned().collect::>()), repeat_keys: Rc::new(repeat_keys.iter().cloned().collect::>()), repeat: None, start_time: Instant::now(), udev: Some(udev_state), xwayland_shell_state: smithay::wayland::xwayland_shell::XWaylandShellState::new::(&display_handle), xwm: None, xwayland_windows: HashMap::new(), xwayland_pending: Vec::new(), ewmh: None, }; let listener = ListeningSocket::bind_auto("wayland", 0..32).map_err(err)?; if let Some(name) = listener.socket_name() { std::env::set_var("WAYLAND_DISPLAY", name); log::info!("wayland socket: {}", name.to_string_lossy()); } // Otherwise this is whatever the session inherited - typically // stale from a *previous* login's compositor (a shell's exported // `XDG_CURRENT_DESKTOP=Hyprland` surviving into this one), since // nothing else ever sets it. `xdg-desktop-portal` and any client // that sniffs this value to pick a desktop-specific integration // (screenshot/file-picker backends, etc.) get actively misrouted by // the stale value rather than just seeing "unknown". Only affects // processes spawned from here on (autostart, `srd.spawn`) - an // env var set mid-process doesn't retroactively reach anything // already running. std::env::set_var("XDG_CURRENT_DESKTOP", "srdwm"); let ipc = match listener.socket_name().map(|n| n.to_string_lossy().into_owned()) { Some(name) => match srdwm_platform::IpcServer::bind(&name) { Ok(ipc) => Some(ipc), Err(e) => { log::warn!("control socket unavailable ({e}); srd and scripts that use it won't work"); None } }, None => None, }; let handle = event_loop.handle(); register_drm_fd(&handle, &card)?; register_libinput(&handle, &session, &seat_name)?; register_session_notifier(&handle, notifier)?; if let Err(e) = register_udev_monitor(&handle, &seat_name) { log::warn!("udev: connector hotplug unavailable ({e}); monitors are fixed at startup"); } if let Err(e) = crate::xwayland::spawn(&handle, &display_handle) { log::warn!("XWayland unavailable ({e}); X11-only clients will not run"); } Ok(Self { event_loop, display: dh, state, listener, clients: Vec::new(), pending, ipc }) } fn accept_clients(&mut self) -> PlatformResult<()> { if let Some(stream) = self.listener.accept().map_err(err)? { let client = self.display.handle().insert_client(stream, std::sync::Arc::new(ClientState::default())).map_err(err)?; self.clients.push(client); } Ok(()) } } fn mode_refresh_mhz(mode: &DrmMode) -> i32 { let vrefresh = mode.vrefresh(); if vrefresh > 0 { vrefresh as i32 * 1000 } else { 60_000 } } /// Brings one connector up: allocates its scanout buffers, sets the mode, /// and creates the `wl_output` global. Shared by startup and hotplug so a /// monitor plugged in later is set up exactly like one present at boot. fn bring_up_head( card: &Card, dh: &DisplayHandle, probe: &ConnectorProbe, crtc: crtc::Handle, x_offset: i32, ) -> PlatformResult<(UdevHead, crate::state::OutputEntry)> { let (width, height) = probe.mode.size(); let (width, height) = (width as i32, height as i32); let buffers = [make_drm_buffer(card, width, height)?, make_drm_buffer(card, width, height)?]; card.set_crtc(crtc, Some(buffers[0].fb), (0, 0), &[probe.connector], Some(probe.mode)).map_err(err)?; // Named after the real connector (eDP-1, HDMI-A-1, ...) so clients and // the user can tell monitors apart; `wl_output.name` is what a bar's // per-monitor config keys off. // // Physical size in millimeters comes straight from EDID via the // connector, not the hardcoded (0, 0) this used to be - some clients // compute their own effective DPI from it (independently of the // compositor's own scale factor, which srdwm always reports as 1), so // reporting "no physical size at all" was live, wrong data reaching // every client, not just an unfilled-in placeholder. let (phys_w, phys_h) = probe.info.size().unwrap_or((0, 0)); let physical_mm = (phys_w as i32, phys_h as i32); let output = Output::new( probe.name.clone(), PhysicalProperties { size: physical_mm.into(), subpixel: Subpixel::Unknown, make: "srdwm".into(), model: "drm".into() }, ); let mode = OutputMode { size: (width, height).into(), refresh: mode_refresh_mhz(&probe.mode) }; output.change_current_state(Some(mode), Some(Transform::Normal), None, Some((x_offset, 0).into())); output.set_preferred(mode); let global = output.create_global::(dh); let location: Point = (x_offset, 0).into(); let head = UdevHead { crtc, connector: probe.connector, output: output.clone(), global, damage_tracker: OutputDamageTracker::from_output(&output), buffers, front: 0, flip_pending: false, ages: [0, 0], location, size: (width, height), }; Ok((head, crate::state::OutputEntry { output, location })) } /// A connected connector and the mode we intend to drive it at. CRTC /// assignment is deliberately separate ([`pick_crtc`]) so a hotplug re-probe /// can leave surviving heads on the CRTCs they already hold. struct ConnectorProbe { connector: connector::Handle, info: connector::Info, mode: DrmMode, /// Connector name as the kernel reports it (`eDP-1`, `HDMI-A-1`, ...). name: String, } /// Every connector currently reporting `Connected`, with its preferred mode. /// /// Forces a fresh probe (`get_connector(.., true)`) rather than trusting /// cached state - on a hotplug the cached status is exactly what has gone /// stale. fn probe_connected(card: &Card) -> PlatformResult> { let res = card.resource_handles().map_err(err)?; let mut probes = Vec::new(); for handle in res.connectors() { let Ok(info) = card.get_connector(*handle, true) else { continue }; if info.state() != connector::State::Connected { continue; } let name = format!("{:?}-{}", info.interface(), info.interface_id()); // Prefer the mode the display advertises as PREFERRED (its native // resolution) rather than whatever happens to be listed first -- // the list order is not guaranteed, and picking wrong means running // a monitor at the wrong resolution. let Some(&mode) = info .modes() .iter() .find(|m| m.mode_type().contains(ModeTypeFlags::PREFERRED)) .or_else(|| info.modes().first()) else { log::warn!("udev: connector {name} is connected but reports no modes; skipping"); continue; }; probes.push(ConnectorProbe { connector: *handle, info, mode, name }); } Ok(probes) } /// Picks a CRTC for `probe` that is not in `used`. /// /// CRTCs are a finite hardware resource and cannot be shared, so a machine /// with more connected monitors than CRTCs drives as many as the hardware /// allows and logs the rest rather than failing outright. fn pick_crtc(card: &Card, probe: &ConnectorProbe, used: &[crtc::Handle]) -> Option { let res = card.resource_handles().ok()?; // Prefer the CRTC already driving this connector, else any free one the // encoder can reach, else anything free at all. probe .info .current_encoder() .and_then(|enc| card.get_encoder(enc).ok()) .map(|enc| res.filter_crtcs(enc.possible_crtcs())) .unwrap_or_default() .into_iter() .chain(res.crtcs().iter().copied()) .find(|c| !used.contains(c)) } fn make_drm_buffer(card: &Card, width: i32, height: i32) -> PlatformResult { let dumb = card.create_dumb_buffer((width as u32, height as u32), DrmFourcc::Xrgb8888, 32).map_err(err)?; let fb = card.add_framebuffer(&dumb, 24, 32).map_err(err)?; let format = FormatCode::try_from(DrmFourcc::Xrgb8888).map_err(|_| PlatformError::Other("udev: unsupported pixel format".into()))?; let image = Image::new(format, width as usize, height as usize, true).map_err(|_| PlatformError::Other("udev: failed to allocate render buffer".into()))?; Ok(DrmBuffer { dumb, fb, image }) } fn register_drm_fd(handle: &LoopHandle<'static, CompState>, card: &Rc) -> PlatformResult<()> { let raw = card.as_fd().as_raw_fd(); // SAFETY: `FdWrapper` does not close `raw`; the owning `Card` lives in // `CompState::udev` for as long as this event source is registered. let wrapper = unsafe { FdWrapper::new(raw) }; let source = Generic::new(wrapper, Interest::READ, CalloopMode::Level); handle .insert_source(source, move |_, _, data: &mut CompState| { let Some(udev) = data.udev.as_ref() else { return Ok(PostAction::Continue) }; let card = udev.card.clone(); match card.receive_events() { Ok(events) => { // The event names the CRTC it came from, so with several // monitors only that head advances - flipping all of // them would desynchronise the others' buffers. let mut flipped = false; for event in events { let DrmEvent::PageFlip(flip) = event else { continue }; if let Some(udev) = data.udev.as_mut() { if let Some(head) = udev.heads.iter_mut().find(|h| h.crtc == flip.crtc) { head.front = 1 - head.front; head.flip_pending = false; flipped = true; } } } if flipped { data.render_udev_frame(); } } Err(e) => log::warn!("udev: receive_events failed: {e}"), } Ok(PostAction::Continue) }) .map_err(|e| PlatformError::Other(format!("failed to register DRM fd: {e}")))?; Ok(()) } fn register_libinput(handle: &LoopHandle<'static, CompState>, session: &LibSeatSession, seat_name: &str) -> PlatformResult<()> { let mut libinput_context = Libinput::new_with_udev::>(session.clone().into()); libinput_context.udev_assign_seat(seat_name).map_err(|_| PlatformError::Other("udev: libinput udev_assign_seat failed".into()))?; let libinput_backend = LibinputInputBackend::new(libinput_context); handle .insert_source(libinput_backend, move |event, _, data: &mut CompState| { handle_libinput_event(data, event); }) .map_err(|e| PlatformError::Other(format!("failed to register libinput backend: {e}")))?; Ok(()) } fn register_session_notifier(handle: &LoopHandle<'static, CompState>, notifier: LibSeatSessionNotifier) -> PlatformResult<()> { handle .insert_source(notifier, move |event, &mut (), data: &mut CompState| { let Some(udev) = data.udev.as_mut() else { return }; match event { SessionEvent::PauseSession => { log::info!("udev: session paused (VT switch away)"); udev.active = false; } SessionEvent::ActivateSession => { log::info!("udev: session resumed (VT switch back)"); udev.active = true; // Some drivers reset mode-setting state across a VT // switch; reassert every head before rendering again. let card = udev.card.clone(); for head in &mut udev.heads { let fb = head.buffers[head.front].fb; if let Err(e) = card.set_crtc(head.crtc, Some(fb), (0, 0), &[], None) { log::warn!("udev: failed to reassert crtc on resume: {e}"); } // Force a full repaint: contents are undefined after // the VT switch (another VT's session may have // scanned out something else entirely in between). head.flip_pending = false; head.ages = [0, 0]; } data.render_udev_frame(); } } }) .map_err(|e| PlatformError::Other(format!("failed to register session notifier: {e}")))?; Ok(()) } /// Watches udev for DRM device changes. The kernel emits a `change` uevent /// on the card when a connector is plugged or unplugged, which smithay /// surfaces as [`UdevEvent::Changed`] - that is the hotplug signal. /// /// `Added`/`Removed` refer to whole GPUs appearing or disappearing, which /// this backend does not support (it binds one primary GPU at startup), so /// they are logged and ignored rather than silently dropped. fn register_udev_monitor(handle: &LoopHandle<'static, CompState>, seat_name: &str) -> PlatformResult<()> { let backend = UdevBackend::new(seat_name).map_err(err)?; handle .insert_source(backend, move |event, _, data: &mut CompState| match event { UdevEvent::Changed { .. } => { data.reprobe_outputs(); data.render_udev_frame(); } UdevEvent::Added { path, .. } => { log::info!("udev: new GPU {} appeared; multi-GPU is not supported, ignoring", path.display()) } UdevEvent::Removed { .. } => log::info!("udev: a GPU was removed; multi-GPU is not supported, ignoring"), }) .map_err(|e| PlatformError::Other(format!("failed to register udev monitor: {e}")))?; Ok(()) } fn handle_libinput_event(state: &mut CompState, event: InputEvent) { match event { InputEvent::Keyboard { event } => handle_keyboard_key_event(state, &event), InputEvent::PointerMotion { event } => { let Some(udev) = state.udev.as_mut() else { return }; let delta = event.delta(); // Clamped to the union of every head, so the pointer travels // between monitors instead of stopping at the first one's edge. let (w, h) = udev.bounds(); udev.pointer_pos.x = (udev.pointer_pos.x + delta.x).clamp(0.0, (w - 1.0).max(0.0)); udev.pointer_pos.y = (udev.pointer_pos.y + delta.y).clamp(0.0, (h - 1.0).max(0.0)); let pos = udev.pointer_pos; handle_pointer_position(state, pos, event.time_msec()); } InputEvent::PointerButton { event } => { let Some(pos) = state.udev.as_ref().map(|u| u.pointer_pos) else { return }; let button = event.button_code(); let pressed = event.state() == BackendButtonState::Pressed; handle_pointer_button(state, pos, button, pressed, event.time_msec()); } // Laptop lid. libinput reports this as a switch toggle; without // handling it, closing the lid does nothing at all - no lock, no // suspend - which is a genuine problem on a laptop rather than a // missing nicety. InputEvent::SwitchToggle { event } => { // Fully qualified: libinput's own `Switch` is also in scope here. use smithay::backend::input::{SwitchState, SwitchToggleEvent}; if matches!(event.switch(), Some(smithay::reexports::input::event::switch::Switch::Lid)) { let closed = event.state() == SwitchState::On; log::info!("lid {}", if closed { "closed" } else { "opened" }); state.pending.borrow_mut().push(CoreEvent::LidSwitch { closed }); } } InputEvent::PointerAxis { event } => { // Modifier+scroll switches workspace instead of reaching the // client - the `bind = SUPER, mouse_down/up, workspace, e+1/e-1` // gesture. Checked first so the client never sees these events; // forwarding them too would scroll the window under the cursor // as a side effect of changing workspace. if crate::input::handle_workspace_scroll(state, &event) { return; } // Otherwise: forwarded to the focused client via the pointer axis // frame, no WM-level handling. let Some(pointer) = state.seat.get_pointer() else { return }; let source = event.source(); let mut frame = AxisFrame::new(event.time_msec()).source(source); for axis in [Axis::Horizontal, Axis::Vertical] { match event.amount(axis) { Some(value) => frame = frame.value(axis, value), // `AxisSource::Finger` (a touchpad) *requires* a stop // event on the frame where the finger lifts and the // axis genuinely has no more motion - see `AxisFrame:: // source`'s own doc comment ("Using AxisSource::Finger // requires a stop event to be sent, when the user lifts // off the finger"). Never sending it left every // two-finger scroll gesture with no way to tell Firefox/ // GTK it had actually ended, which is exactly the kind // of thing that reads as "scrolling doesn't work" -- // not "no events arrive" (discrete wheel scrolling, // which needs no stop event, was never affected) but // kinetic/momentum scrolling and starting a fresh // gesture right after a previous one never settling. None if source == AxisSource::Finger => frame = frame.stop(axis), None => {} } // Discrete wheel steps, additional to the pixel `value` // above - optional (`value` is the only event a client // strictly needs), but some clients use it to distinguish // "one physical click" from a smooth/high-resolution // scroll, so provide it whenever the device actually // reports one (real scroll wheels; never touchpads, which // have no discrete steps to report - `amount_v120` is // `None` for those, same guarantee `amount` gives the // other way around). if let Some(v120) = event.amount_v120(axis) { frame = frame.v120(axis, v120 as i32); } } pointer.axis(state, frame); pointer.frame(state); } _ => {} } } impl Platform for UdevPlatform { fn kind(&self) -> PlatformKind { PlatformKind::Wayland } fn poll_events(&mut self) -> PlatformResult> { self.accept_clients()?; self.event_loop.dispatch(Some(Duration::from_millis(16)), &mut self.state).map_err(err)?; // Held bindings that repeat - see `CompState::tick_repeat`. self.state.tick_repeat(); self.display.dispatch_clients(&mut self.state).map_err(err)?; self.display.flush_clients().map_err(err)?; if let Some(ipc) = self.ipc.as_mut() { if ipc.poll(&self.state.wm) { self.pending.borrow_mut().push(CoreEvent::WorkspaceChanged); } } self.state.render_udev_frame(); Ok(self.pending.borrow_mut().drain(..).collect()) } /// One `srdwm_core::Monitor` per head, positioned in the global space. /// This is what makes core's layout engine multi-monitor-aware in /// practice: `arrange_workspace` groups windows by `monitor` and lays /// each group out inside that monitor's rectangle. fn monitors(&mut self) -> PlatformResult> { let Some(udev) = self.state.udev.as_ref() else { return Ok(Vec::new()) }; Ok(udev .heads .iter() .enumerate() .map(|(i, head)| { // Shrunk by whatever a layer-shell surface (bar, dock) has // reserved via `set_exclusive_zone` - reporting the full // head size here otherwise means core's placement/tiling // treats that strip as ordinary free space, so a new // window's titlebar lands right where the bar renders on // top of it, unreachable to drag. `non_exclusive_zone()` is // output-local, so it's translated into this head's // position in the shared global space the same way // `head.location` already is. let zone = layer_map_for_output(&head.output).non_exclusive_zone(); let rect = srdwm_core::Rect::new( head.location.x + zone.loc.x, head.location.y + zone.loc.y, zone.size.w as u32, zone.size.h as u32, ); let mut m = srdwm_core::Monitor::new(i as u32, head.output.name(), rect); // `Monitor::new` defaults `full_geometry` to whatever // `geometry` was constructed with - correct for a monitor // with no layer-shell client at all, wrong the moment one // exists, since `rect` above is already zone-shrunk. Without // this, `full_geometry` was silently identical to `geometry` // for every real monitor this backend ever reported, which // made `toggle_fullscreen`'s whole "ignore the reserved // zone" design a no-op in practice: fullscreen still // stopped at the bar/dock exactly like maximize does. // Reported live as "fullscreen isn't actually going // fullscreen" - confirmed by triggering it and reading // the resulting geometry back over IPC, not just from // reading this code. m.full_geometry = srdwm_core::Rect::new(head.location.x, head.location.y, head.size.0 as u32, head.size.1 as u32); m.primary = i == 0; m }) .collect()) } fn apply_geometry(&mut self, window: srdwm_core::WindowId, _geometry: srdwm_core::Rect) -> PlatformResult<()> { self.state.sync_geometry(window); Ok(()) } fn set_title(&mut self, _window: srdwm_core::WindowId, _title: &str) -> PlatformResult<()> { Ok(()) } /// Was `wm.focus_window(window)` alone - core-only, so a caller that /// only has `Platform` to go through (`crates/platform`'s `IpcServer`, /// which can't reach `CompState`/real Wayland focus at all) could make /// a window *look* focused (rendering already reads live core state /// for the highlighted-border/titlebar-text colour) without it ever /// actually receiving a keystroke - confirmed live: `srd dispatch /// focus ` changed core's own focused-window /// bookkeeping but left `_NET_ACTIVE_WINDOW` at `0x0` and real /// keyboard input going nowhere. `crate::input::focus_window` is the /// same full path a real mouse click already goes through. fn focus(&mut self, window: srdwm_core::WindowId) -> PlatformResult<()> { crate::input::focus_window(&mut self.state, window); Ok(()) } fn minimize(&mut self, window: srdwm_core::WindowId) -> PlatformResult<()> { if let Some(w) = self.state.id_to_window.get(&window) { self.state.space.unmap_elem(w); } Ok(()) } fn restore(&mut self, window: srdwm_core::WindowId) -> PlatformResult<()> { self.state.sync_geometry(window); Ok(()) } fn close(&mut self, window: srdwm_core::WindowId) -> PlatformResult<()> { if let Some(w) = self.state.id_to_window.get(&window).and_then(|w| w.toplevel()) { w.send_close(); } Ok(()) } fn set_decorated(&mut self, _window: srdwm_core::WindowId, _decorated: bool) -> PlatformResult<()> { Ok(()) } fn set_border_color(&mut self, _window: srdwm_core::WindowId, _rgb: (u8, u8, u8)) -> PlatformResult<()> { Ok(()) } fn set_border_width(&mut self, _window: srdwm_core::WindowId, _width: u32) -> PlatformResult<()> { Ok(()) } fn redraw_decoration(&mut self, window: srdwm_core::WindowId, _win: &srdwm_core::Window, _focused: bool) -> PlatformResult<()> { self.state.redraw_decoration_buffer(window); self.state.sync_geometry(window); Ok(()) } fn grab_keyboard(&mut self) -> PlatformResult<()> { Ok(()) } fn ungrab_keyboard(&mut self) -> PlatformResult<()> { Ok(()) } }