Try to recover from GPU resets

Use context robustness to get notified about GPU resets
and try to recover from them by rebuilding the rendering
pipeline.

4 files changed, 122 insertions, 23 deletions

diff --git a/alacritty/build.rs b/alacritty/build.rs
index 7c33040e..0856e3a5 100644
--- a/alacritty/build.rs
+++ b/alacritty/build.rs
@@ -17,6 +17,7 @@ fn main() {
 
     Registry::new(Api::Gl, (3, 3), Profile::Core, Fallbacks::All, [
         "GL_ARB_blend_func_extended",
+        "GL_KHR_robustness",
         "GL_KHR_debug",
     ])
     .write_bindings(GlobalGenerator, &mut file)
diff --git a/alacritty/src/display/mod.rs b/alacritty/src/display/mod.rs
index 6c685a2a..9f11ccf6 100644
--- a/alacritty/src/display/mod.rs
+++ b/alacritty/src/display/mod.rs
@@ -8,7 +8,10 @@ use std::num::NonZeroU32;
 use std::ops::{Deref, DerefMut};
 use std::time::{Duration, Instant};
 
+use glutin::config::GetGlConfig;
 use glutin::context::{NotCurrentContext, PossiblyCurrentContext};
+use glutin::display::GetGlDisplay;
+use glutin::error::ErrorKind;
 use glutin::prelude::*;
 use glutin::surface::{Surface, SwapInterval, WindowSurface};
 
@@ -33,6 +36,7 @@ use alacritty_terminal::term::{
 };
 use alacritty_terminal::vte::ansi::{CursorShape, NamedColor};
 
+use crate::config::debug::RendererPreference;
 use crate::config::font::Font;
 use crate::config::window::Dimensions;
 #[cfg(not(windows))]
@@ -49,7 +53,7 @@ use crate::display::window::Window;
 use crate::event::{Event, EventType, Mouse, SearchState};
 use crate::message_bar::{MessageBuffer, MessageType};
 use crate::renderer::rects::{RenderLine, RenderLines, RenderRect};
-use crate::renderer::{self, GlyphCache, Renderer};
+use crate::renderer::{self, platform, GlyphCache, Renderer};
 use crate::scheduler::{Scheduler, TimerId, Topic};
 use crate::string::{ShortenDirection, StrShortener};
 
@@ -385,6 +389,7 @@ pub struct Display {
     hint_mouse_point: Option<Point>,
 
     renderer: ManuallyDrop<Renderer>,
+    renderer_preference: Option<RendererPreference>,
 
     surface: ManuallyDrop<Surface<WindowSurface>>,
 
@@ -421,7 +426,7 @@ impl Display {
         }
 
         // Create the GL surface to draw into.
-        let surface = renderer::platform::create_gl_surface(
+        let surface = platform::create_gl_surface(
             &gl_context,
             window.inner_size(),
             window.raw_window_handle(),
@@ -513,6 +518,7 @@ impl Display {
             context: ManuallyDrop::new(Replaceable::new(context)),
             visual_bell: VisualBell::from(&config.bell),
             renderer: ManuallyDrop::new(renderer),
+            renderer_preference: config.debug.renderer,
             surface: ManuallyDrop::new(surface),
             colors: List::from(&config.colors),
             frame_timer: FrameTimer::new(),
@@ -552,10 +558,55 @@ impl Display {
         }
     }
 
-    pub fn make_current(&self) {
-        if !self.context.get().is_current() {
-            self.context.make_current(&self.surface).expect("failed to make context current")
+    pub fn make_current(&mut self) {
+        let is_current = self.context.get().is_current();
+
+        // Attempt to make the context current if it's not.
+        let context_loss = if is_current {
+            self.renderer.was_context_reset()
+        } else {
+            match self.context.make_current(&self.surface) {
+                Err(err) if err.error_kind() == ErrorKind::ContextLost => {
+                    info!("Context lost for window {:?}", self.window.id());
+                    true
+                },
+                _ => false,
+            }
+        };
+
+        if !context_loss {
+            return;
+        }
+
+        let gl_display = self.context.display();
+        let gl_config = self.context.config();
+        let raw_window_handle = Some(self.window.raw_window_handle());
+        let context = platform::create_gl_context(&gl_display, &gl_config, raw_window_handle)
+            .expect("failed to recreate context.");
+
+        // Drop the old context and renderer.
+        unsafe {
+            ManuallyDrop::drop(&mut self.renderer);
+            ManuallyDrop::drop(&mut self.context);
         }
+
+        // Activate new context.
+        let context = context.treat_as_possibly_current();
+        self.context = ManuallyDrop::new(Replaceable::new(context));
+        self.context.make_current(&self.surface).expect("failed to reativate context after reset.");
+
+        // Recreate renderer.
+        let renderer = Renderer::new(&self.context, self.renderer_preference)
+            .expect("failed to recreate renderer after reset");
+        self.renderer = ManuallyDrop::new(renderer);
+
+        // Resize the renderer.
+        self.renderer.resize(&self.size_info);
+
+        self.reset_glyph_cache();
+        self.damage_tracker.frame().mark_fully_damaged();
+
+        debug!("Recovered window {:?} from gpu reset", self.window.id());
     }
 
     fn swap_buffers(&self) {
diff --git a/alacritty/src/renderer/mod.rs b/alacritty/src/renderer/mod.rs
index 3362db42..92998e58 100644
--- a/alacritty/src/renderer/mod.rs
+++ b/alacritty/src/renderer/mod.rs
@@ -9,7 +9,7 @@ use ahash::RandomState;
 use crossfont::Metrics;
 use glutin::context::{ContextApi, GlContext, PossiblyCurrentContext};
 use glutin::display::{GetGlDisplay, GlDisplay};
-use log::{debug, error, info, warn, LevelFilter};
+use log::{debug, info, LevelFilter};
 use unicode_width::UnicodeWidthChar;
 
 use alacritty_terminal::index::Point;
@@ -97,6 +97,7 @@ enum TextRendererProvider {
 pub struct Renderer {
     text_renderer: TextRendererProvider,
     rect_renderer: RectRenderer,
+    robustness: bool,
 }
 
 /// Wrapper around gl::GetString with error checking and reporting.
@@ -144,6 +145,9 @@ impl Renderer {
         info!("Running on {renderer}");
         info!("OpenGL version {gl_version}, shader_version {shader_version}");
 
+        // Check if robustness is supported.
+        let robustness = Self::supports_robustness();
+
         let is_gles_context = matches!(context.context_api(), ContextApi::Gles(_));
 
         // Use the config option to enforce a particular renderer configuration.
@@ -175,7 +179,7 @@ impl Renderer {
             }
         }
 
-        Ok(Self { text_renderer, rect_renderer })
+        Ok(Self { text_renderer, rect_renderer, robustness })
     }
 
     pub fn draw_cells<I: Iterator<Item = RenderableCell>>(
@@ -281,6 +285,49 @@ impl Renderer {
         }
     }
 
+    /// Get the context reset status.
+    pub fn was_context_reset(&self) -> bool {
+        // If robustness is not supported, don't use its functions.
+        if !self.robustness {
+            return false;
+        }
+
+        let status = unsafe { gl::GetGraphicsResetStatus() };
+        if status == gl::NO_ERROR {
+            false
+        } else {
+            let reason = match status {
+                gl::GUILTY_CONTEXT_RESET_KHR => "guilty",
+                gl::INNOCENT_CONTEXT_RESET_KHR => "innocent",
+                gl::UNKNOWN_CONTEXT_RESET_KHR => "unknown",
+                _ => "invalid",
+            };
+
+            info!("GPU reset ({})", reason);
+
+            true
+        }
+    }
+
+    fn supports_robustness() -> bool {
+        let mut notification_strategy = 0;
+        if GlExtensions::contains("GL_KHR_robustness") {
+            unsafe {
+                gl::GetIntegerv(gl::RESET_NOTIFICATION_STRATEGY_KHR, &mut notification_strategy);
+            }
+        } else {
+            notification_strategy = gl::NO_RESET_NOTIFICATION_KHR as gl::types::GLint;
+        }
+
+        if notification_strategy == gl::LOSE_CONTEXT_ON_RESET_KHR as gl::types::GLint {
+            info!("GPU reset notifications are enabled");
+            true
+        } else {
+            info!("GPU reset notifications are disabled");
+            false
+        }
+    }
+
     pub fn finish(&self) {
         unsafe {
             gl::Finish();
@@ -349,7 +396,7 @@ impl GlExtensions {
 
 extern "system" fn gl_debug_log(
     _: gl::types::GLenum,
-    kind: gl::types::GLenum,
+    _: gl::types::GLenum,
     _: gl::types::GLuint,
     _: gl::types::GLenum,
     _: gl::types::GLsizei,
@@ -357,11 +404,5 @@ extern "system" fn gl_debug_log(
     _: *mut std::os::raw::c_void,
 ) {
     let msg = unsafe { CStr::from_ptr(msg).to_string_lossy() };
-    match kind {
-        gl::DEBUG_TYPE_ERROR | gl::DEBUG_TYPE_UNDEFINED_BEHAVIOR => {
-            error!("[gl_render] {}", msg)
-        },
-        gl::DEBUG_TYPE_DEPRECATED_BEHAVIOR => warn!("[gl_render] {}", msg),
-        _ => debug!("[gl_render] {}", msg),
-    }
+    debug!("[gl_render] {}", msg);
 }
diff --git a/alacritty/src/renderer/platform.rs b/alacritty/src/renderer/platform.rs
index 87ed29c2..3b2e2fce 100644
--- a/alacritty/src/renderer/platform.rs
+++ b/alacritty/src/renderer/platform.rs
@@ -4,9 +4,9 @@ use std::num::NonZeroU32;
 
 use glutin::config::{ColorBufferType, Config, ConfigTemplateBuilder, GetGlConfig};
 use glutin::context::{
-    ContextApi, ContextAttributesBuilder, GlProfile, NotCurrentContext, Version,
+    ContextApi, ContextAttributesBuilder, GlProfile, NotCurrentContext, Robustness, Version,
 };
-use glutin::display::{Display, DisplayApiPreference, GetGlDisplay};
+use glutin::display::{Display, DisplayApiPreference, DisplayFeatures, GetGlDisplay};
 use glutin::error::Result as GlutinResult;
 use glutin::prelude::*;
 use glutin::surface::{Surface, SurfaceAttributesBuilder, WindowSurface};
@@ -110,18 +110,24 @@ pub fn create_gl_context(
     raw_window_handle: Option<RawWindowHandle>,
 ) -> GlutinResult<NotCurrentContext> {
     let debug = log::max_level() >= LevelFilter::Debug;
+    let mut builder = ContextAttributesBuilder::new().with_debug(debug);
+
+    // Try to enable robustness.
+    if gl_display.supported_features().contains(DisplayFeatures::CONTEXT_ROBUSTNESS) {
+        builder = builder.with_robustness(Robustness::RobustLoseContextOnReset);
+    }
+
     let mut profiles = [
-        ContextAttributesBuilder::new()
-            .with_debug(debug)
+        builder
+            .clone()
             .with_context_api(ContextApi::OpenGl(Some(Version::new(3, 3))))
             .build(raw_window_handle),
         // Try gles before OpenGL 2.1 as it tends to be more stable.
-        ContextAttributesBuilder::new()
-            .with_debug(debug)
+        builder
+            .clone()
             .with_context_api(ContextApi::Gles(Some(Version::new(2, 0))))
             .build(raw_window_handle),
-        ContextAttributesBuilder::new()
-            .with_debug(debug)
+        builder
             .with_profile(GlProfile::Compatibility)
             .with_context_api(ContextApi::OpenGl(Some(Version::new(2, 1))))
             .build(raw_window_handle),