Files
marfrit-packages/arch/qt6-base-fourier/patches/0002-qrhigles2-RED_OR_ALPHA8-pick-GL_R8-on-ES3.patch
T
marfrit 1dada5122b qt6-base-fourier: GL_ALPHA → GL_R8 on OpenGL ES 3.x
Three small runtime checks in qtbase 6.11.0:

1. src/opengl/qopengltextureglyphcache.cpp createTextureData() and
   load_glyph_image_to_texture() — the `#else` branch (active when
   qtbase is built with QT_CONFIG(opengles2), every aarch64 distro)
   hard-codes GL_ALPHA without checking the runtime context's ES
   version. Replace with `useR8 = ctx->format().majorVersion() >= 3`
   so ES 3+ contexts get GL_R8 + GL_RED.

2. src/gui/rhi/qrhigles2.cpp toGlTextureFormat() RED_OR_ALPHA8 case
   — gated only on caps.coreProfile. Extend with
   `caps.gles && caps.ctxMajor >= 3`.

3. src/opengl/qopengltextureuploader.cpp Format_Alpha8 and
   Format_Grayscale8 cases — short-circuit on `context->isOpenGLES()`
   before reaching the swizzle fallback. Restrict to ES 2 only so
   ES 3+ falls through to the existing TextureSwizzle path.

Discovered while validating chromium-fourier patch 3/3 (NV12
EXTERNAL_OES) on ohm. The chrome stall, VLC vout init failure and
mpv "could not initialize video chain" all share this Qt 6 root
cause: every Qt application running on Mali / panfrost / panthor
under a KWin Wayland session emits glTexImage2D(GL_ALPHA) on every
text-glyph cache upload, mesa returns GL_INVALID_VALUE, the
compositor's frame-callback path stalls, and every wayland video
client deadlocks behind it.

PKGBUILD inherits from extra/qt6-base 6.11.0-2 with arch+=aarch64,
epoch=1 to dominate Arch's pkgrel until upstream lands the fix.
qt6-base-cflags.patch and qt6-base-nostrip.patch carried verbatim
from upstream packaging.

KWIN_PIVOT.md (in chromium-fourier/) carries the full diagnosis
thread.
2026-04-28 12:35:08 +00:00

34 lines
1.4 KiB
Diff

diff --git a/src/gui/rhi/qrhigles2.cpp b/src/gui/rhi/qrhigles2.cpp
index 5208bd4d..a2625949 100644
--- a/src/gui/rhi/qrhigles2.cpp
+++ b/src/gui/rhi/qrhigles2.cpp
@@ -1367,18 +1367,25 @@ static inline void toGlTextureFormat(QRhiTexture::Format format, const QRhiGles2
case QRhiTexture::RG8:
*glintformat = GL_RG8;
*glsizedintformat = *glintformat;
*glformat = GL_RG;
*gltype = GL_UNSIGNED_BYTE;
break;
- case QRhiTexture::RED_OR_ALPHA8:
- *glintformat = caps.coreProfile ? GL_R8 : GL_ALPHA;
+ case QRhiTexture::RED_OR_ALPHA8: {
+ // qt6-base-fourier: GL_ALPHA was removed from the valid
+ // glTexImage2D internalFormat list in OpenGL ES 3.0 (ES 3
+ // spec section 3.8.3). Pick GL_R8 + GL_RED for desktop GL
+ // Core profile and for any ES 3 or newer context; only
+ // legacy ES 2 contexts retain GL_ALPHA.
+ const bool useR8 = caps.coreProfile || (caps.gles && caps.ctxMajor >= 3);
+ *glintformat = useR8 ? GL_R8 : GL_ALPHA;
*glsizedintformat = *glintformat;
- *glformat = caps.coreProfile ? GL_RED : GL_ALPHA;
+ *glformat = useR8 ? GL_RED : GL_ALPHA;
*gltype = GL_UNSIGNED_BYTE;
break;
+ }
case QRhiTexture::RGBA16F:
*glintformat = GL_RGBA16F;
*glsizedintformat = *glintformat;
*glformat = GL_RGBA;
*gltype = GL_HALF_FLOAT;
break;