From: Markus Fritsche <mfritsche@reauktion.de>
Subject: ozone/wayland: re-allow direct EGL/GLES2 path (no ANGLE shim)
Date: 2026-04-26

Background
----------
On Wayland-only ozone builds the surface factory currently advertises only
ANGLE-mediated GL implementations (`kOpenGL`, `kOpenGLES`, `kSwiftShader`,
`kVulkan`). Anything driving `--use-gl=egl` (the historical
`kGLImplementationEGLGLES2`) is rejected at startup with

    Requested GL implementation (gl=egl-gles2,angle=none) not found in
    allowed implementations: [(gl=egl-angle,angle=opengl|opengles|...)]

The downstream switch already handles `kGLImplementationEGLGLES2` in
`GetGLOzone`, so the dispatcher is wired -- it's the *advertisement* that
got tightened.

The cost of that tightening on RK3566 hantro / panfrost is real: with
ANGLE in the path, chrome's display-side EGL is ANGLE's own EGL. ANGLE's
GLES backend on Linux does not propagate
`EGL_EXT_image_dma_buf_import` through to the chrome GL display, so
`gpu_feature_info.supports_nv12_gl_native_pixmap` ends up false. That in
turn forces the V4L2-decoded NV12 frames through the
NV12-to-AR24 VPP conversion path before they hit the compositor, costing
~85 % CPU at 1080p30 even though the hantro VPU is doing the actual
decode for free.

Allowing the direct EGL/GLES2 path back means chrome's EGL is panfrost's
EGL (via mesa), which exposes the dmabuf-import extensions natively, and
the zero-copy NV12 native pixmap path lights up.

Fix
---
Add `kGLImplementationEGLGLES2` to the head of the allowed list; ANGLE
remains the default fallback and is still selected when the user passes
`--use-gl=angle ...`. The position is deliberate: on a USE_V4L2_CODEC
hardware-decode build the user almost always wants the dmabuf-capable
direct path; ANGLE is still there for browsers that need its conformance
fixups.

This does not affect non-Wayland ozone backends.

diff --git a/ui/ozone/platform/wayland/gpu/wayland_surface_factory.cc b/ui/ozone/platform/wayland/gpu/wayland_surface_factory.cc
--- a/ui/ozone/platform/wayland/gpu/wayland_surface_factory.cc
+++ b/ui/ozone/platform/wayland/gpu/wayland_surface_factory.cc
@@ -223,6 +223,10 @@ std::vector<gl::GLImplementationParts>
 WaylandSurfaceFactory::GetAllowedGLImplementations() {
   std::vector<gl::GLImplementationParts> impls;
   if (egl_implementation_) {
+    // chromium-fourier: keep the direct EGL/GLES2 path available so
+    // panfrost's EGL_EXT_image_dma_buf_import surfaces to chrome's GL
+    // display layer. See patch header for rationale.
+    impls.emplace_back(gl::GLImplementationParts(gl::kGLImplementationEGLGLES2));
     impls.emplace_back(gl::ANGLEImplementation::kOpenGL);
     impls.emplace_back(gl::ANGLEImplementation::kOpenGLES);
     impls.emplace_back(gl::ANGLEImplementation::kSwiftShader);