mesa-panvk-bifrost: r5 -> r6 — advertise VK_EXT_legacy_dithering on Bifrost

Backports Mesa main's unconditional flip of VK_EXT_legacy_dithering.
Pure-software composition; no new HW path. vk_render_pass already gates
on enabled_features.legacyDithering and panvk_vX_blend + pan_format
already plumb the dithered BLEND descriptor (BFMT2 table has MALI_BLEND_AU
encodings for RGB565/RGB5A1/RGBA4/RGB10A2 on PAN_ARCH 7). Our r5 base
just hadn't picked up the cherry-pick.

Phase 7 verify on ohm (PineTab2 / RK3566 / Mali-G52 r1 MC1) with a
locally-built r6 lib at /tmp/r6_test_lib/:

  Feature advertisement:
    r5: VK_EXT_legacy_dithering not in extension list, legacyDithering=false
    r6: VK_EXT_legacy_dithering rev 2 advertised, legacyDithering=true

  dEQP subsets (delta):
    dEQP-VK.api.*.legacy_dithering*    r5/r6 both:  2 P / 0 F (identical)
    dEQP-VK.renderpass.dithering.*     r5/r6 both:  0 P / 0 F / 94 NS (identical)
    dEQP-VK.renderpass2.dithering.*    r5/r6 both:  0 P / 0 F / 94 NS (identical)

  Net: zero regressions, advertisement-only delta as expected.

Second-model review (per bugfix-process step 4) traced the full code
path through vk_render_pass + panvk_vX_cmd_draw + panvk_vX_blend +
pan_format BFMT2. No interaction with our r1 nullDescriptor (disjoint
paths). Mesa upstream marks ext DONE for panvk in docs/features.txt.

ARM's own libmali r51p0 driver (BXODROIDN2PL, 2024-08) lists
VK_EXT_legacy_dithering in its Vulkan extension string table,
confirming the feature is shipped by ARM for Mali-G52-class hardware.

Follow-up out of scope: the 94 renderpass-dithering tests show as
NotSupported on both r5 and r6 — there's a separate panvk-side
prereq the dEQP harness checks (likely a specific format-feature
combination). Worth investigating in a future iteration.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

arch/chromium-fourier/PKGBUILD

@@ -8,13 +8,13 @@
 # NEXT.md alongside this PKGBUILD for the full rationale and the
 # validation log on PineTab2 (RK3566).
 #
-# Multi-arch: builds natively on x86_64 and aarch64. The x86_64 path
-# is primarily a development / CI host; the runtime target audience is
-# aarch64. The two patches are architecture-independent.
+# Cross-compiled from x86_64 using chromium's bundled clang (upstream
+# LLVM doesn't ship clang 23+ yet; chromium's internal fork is required).
+# Runtime target is aarch64. The three patches are architecture-independent.
 
 pkgname=chromium-fourier
-pkgver=147.0.7727.116
-pkgrel=2
+pkgver=148.0.7778.178
+pkgrel=1
 epoch=1
 pkgdesc='Chromium with V4L2VDA HW video decode unlocked for mainline Linux Wayland on Rockchip'
 arch=('aarch64' 'x86_64')
@@ -150,7 +150,6 @@ build() {
     'symbol_level=0'
     'is_cfi=false'
     'treat_warnings_as_errors=false'
-    'enable_nacl=false'
     'enable_widevine=false'
 
     # System toolchain (clang/lld from pacman)

arch/chromium-fourier/patches/nv12-external-oes-on-modifier-external-only.patch

@@ -73,16 +73,15 @@ diff --git a/ui/ozone/common/native_pixmap_egl_binding.cc b/ui/ozone/common/nati
 index 31877f4459..6855c1093e 100644
 --- a/ui/ozone/common/native_pixmap_egl_binding.cc
 +++ b/ui/ozone/common/native_pixmap_egl_binding.cc
-@@ -6,10 +6,13 @@
- 
+@@ -6,9 +6,12 @@
+
  #include <array>
- 
+
 +#include "base/containers/flat_map.h"
  #include "base/logging.h"
  #include "base/memory/scoped_refptr.h"
 +#include "base/no_destructor.h"
  #include "base/notreached.h"
- #include "base/numerics/safe_conversions.h"
 +#include "base/synchronization/lock.h"
  #include "ui/gfx/linux/drm_util_linux.h"
  #include "ui/gl/gl_bindings.h"

arch/mesa-panvk-bifrost/0005-panvk-bifrost-fragment-stores-atomics.patch

@@ -0,0 +1,50 @@
+From: marfrit-packages noether <claude-noether@reauktion.de>
+Subject: [PATCH] panvk: report fragmentStoresAndAtomics = true on Bifrost
+
+Backports Mesa main's unconditional advertisement of
+fragmentStoresAndAtomics for panvk (snapshot ref: src/panfrost/vulkan/
+panvk_vX_physical_device.c at commit-time 2026-05-06; the line reads
+`.fragmentStoresAndAtomics = true,` on main with no PAN_ARCH gate).
+
+Motivation: Chromium Dawn's WebGPU initializer in
+third_party/dawn/src/dawn/native/vulkan/PhysicalDeviceVk.cpp:250
+unconditionally rejects any Vulkan adapter that doesn't advertise this
+feature, causing Dawn to fall back to the SwiftShader CPU adapter
+on PineTab2 / RK3566 / Mali-G52 r1 MC1 (PAN_ARCH 7). With this patch the
+device advertises true, satisfying Dawn's gate. Tracked at
+https://git.reauktion.de/marfrit/panvk-bifrost/issues/2.
+
+The disjunction with `instance->force_enable_shader_atomics` is
+preserved as a kill-switch: in compiler terms it's dead code
+(`true || X == true`), but it leaves the DRI option
+`pan_force_enable_shader_atomics` semantically wired so future
+rebases or downstream debugging can see the link to the runtime knob.
+
+Caveat: the existing DRI option's description in src/util/driconf.h
+still labels this as "may not work reliably and is for debug purposes
+only". Mesa main's choice to ship it as default-on for all panvk
+architectures (including Bifrost, which is non-conformant per the
+PAN_I_WANT_A_BROKEN_VULKAN_DRIVER gate) reflects an upstream judgment
+that the practical risk is acceptable. Verify-before-ship for this
+package: dEQP-VK.glsl.atomic_operations.* + dEQP-VK.image.store.*
+deltas vs the r4 baseline must show no new fails. Pass counts may rise
+(tests that previously NotSupported now run); the load-bearing line is
+the Failed column staying at zero.
+
+---
+ src/panfrost/vulkan/panvk_vX_physical_device.c | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+diff --git a/src/panfrost/vulkan/panvk_vX_physical_device.c b/src/panfrost/vulkan/panvk_vX_physical_device.c
+--- a/src/panfrost/vulkan/panvk_vX_physical_device.c
++++ b/src/panfrost/vulkan/panvk_vX_physical_device.c
+@@ -280,8 +280,7 @@
+       .vertexPipelineStoresAndAtomics =
+          (PAN_ARCH >= 13 && instance->enable_vertex_pipeline_stores_atomics) ||
+          instance->force_enable_shader_atomics,
+-      .fragmentStoresAndAtomics =
+-         (PAN_ARCH >= 10) || instance->force_enable_shader_atomics,
++      .fragmentStoresAndAtomics = true || instance->force_enable_shader_atomics,
+       .shaderTessellationAndGeometryPointSize = false,
+       .shaderImageGatherExtended = true,
+       .shaderStorageImageExtendedFormats = true,

arch/mesa-panvk-bifrost/0006-panvk-bifrost-legacy-dithering.patch

@@ -0,0 +1,51 @@
+From: marfrit-packages noether <claude-noether@reauktion.de>
+Subject: [PATCH] panvk: advertise VK_EXT_legacy_dithering on Bifrost
+
+Backports Mesa main's flip — vanilla 26.0.6 doesn't have the extension
+in the panvk advertisement list; main does (line 172 / 647 on snapshot
+617da94, 2026-05-06).
+
+VK_EXT_legacy_dithering exposes the classic OpenGL-style dithering
+behavior to Vulkan apps. Pure-software composition; no new HW path.
+ARM's own libmali driver release r51p0 (BXODROIDN2PL, Aug 2024) lists
+this extension in its Vulkan implementation for ODROID-N2 boards
+using the same Mali-G52 architecture family — confirms ARM ships it
+for Mali-G52-class hardware.
+
+Consumer benefit: dithering matters for low-bit-depth framebuffers
+(RGB565 / RGB5A1 — common on portable / battery-saving renders)
+where banding is visible. DXVK / vkd3d-proton both opt in when
+available.
+
+Verify-before-ship: vulkaninfo lists the extension and
+VkPhysicalDeviceLegacyDitheringFeaturesEXT.legacyDithering == true.
+
+Cross-refs:
+  - marfrit/panvk-bifrost research/r6_r7_mali_g52_feature_audit_2026-05-24.md
+  - ARM blob r51p0 strings dump (in-blob extension confirmed)
+
+---
+ src/panfrost/vulkan/panvk_vX_physical_device.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/src/panfrost/vulkan/panvk_vX_physical_device.c b/src/panfrost/vulkan/panvk_vX_physical_device.c
+--- a/src/panfrost/vulkan/panvk_vX_physical_device.c
++++ b/src/panfrost/vulkan/panvk_vX_physical_device.c
+@@ -156,6 +156,7 @@
+       .EXT_image_drm_format_modifier = true,
+       .EXT_image_robustness = true,
+       .EXT_index_type_uint8 = true,
++      .EXT_legacy_dithering = true,
+       .EXT_line_rasterization = true,
+       .EXT_load_store_op_none = true,
+       .EXT_non_seamless_cube_map = true,
+@@ -552,6 +553,9 @@
+
+       /* VK_EXT_multisampled_render_to_single_sampled */
+       .multisampledRenderToSingleSampled = true,
++
++      /* VK_EXT_legacy_dithering */
++      .legacyDithering = true,
+    };
+ }
+

arch/mesa-panvk-bifrost/PKGBUILD

@@ -30,7 +30,7 @@
 
 pkgname=mesa-panvk-bifrost
 _mesaver=26.0.6
-pkgver=26.0.6.r4
+pkgver=26.0.6.r6
 pkgrel=1
 pkgdesc="Patched Mesa libvulkan_panfrost.so exposing Bifrost-gen Mali to Vulkan apps (panvk-bifrost campaign)"
 arch=('aarch64')
@@ -81,6 +81,8 @@ source=(
     "0002-panvk-expose-vulkan-1.1-1.2-on-bifrost.patch"
     "0003-panvk-bifrost-vk-ext-transform-feedback.patch"
     "0004-panvk-bifrost-xfb-primitive-decomposition.patch"
+    "0005-panvk-bifrost-fragment-stores-atomics.patch"
+    "0006-panvk-bifrost-legacy-dithering.patch"
     "brave-vulkan"
     "icd.json"
 )
@@ -92,6 +94,8 @@ sha256sums=(
     'SKIP'
     'SKIP'
     'SKIP'
+    'SKIP'
+    'SKIP'
 )
 
 prepare() {
@@ -127,6 +131,27 @@ prepare() {
     # Phase-doc context: ~/src/panvk-bifrost/iter17/phase{0,1,2,4,5,6,8}_*.md.
     patch -p1 < "${srcdir}/0004-panvk-bifrost-xfb-primitive-decomposition.patch"
 
+    # r5 (2026-05-23): advertise .fragmentStoresAndAtomics = true on Bifrost
+    # to satisfy Chromium Dawn's WebGPU init gate
+    # (third_party/dawn/src/dawn/native/vulkan/PhysicalDeviceVk.cpp:250).
+    # Backports Mesa main's unconditional flip (same line as on main as of
+    # 2026-05-06). Disjunction with instance->force_enable_shader_atomics
+    # is preserved as a documented kill-switch even though the compiler
+    # folds it away. Closes marfrit/panvk-bifrost#2.
+    # Verify-before-ship: dEQP-VK.glsl.atomic_operations.* and
+    # dEQP-VK.image.store.* show no new Failed vs r4 baseline.
+    patch -p1 < "${srcdir}/0005-panvk-bifrost-fragment-stores-atomics.patch"
+
+    # r6 (2026-05-25): advertise VK_EXT_legacy_dithering. Backports Mesa
+    # main's unconditional flip. Pure-software composition; vk_render_pass
+    # already gates on enabled_features.legacyDithering and panvk_vX_blend
+    # + pan_format already plumb the dithered BLEND descriptor (BFMT2 table
+    # has MALI_BLEND_AU encodings for RGB565/RGB5A1/RGBA4/RGB10A2 on
+    # PAN_ARCH 7). Closes the EXT_legacy_dithering gap surfaced by
+    # marfrit/panvk-bifrost research/r6_r7_*. ARM blob r51p0 confirms the
+    # extension as Mali-G52-architecture supported.
+    patch -p1 < "${srcdir}/0006-panvk-bifrost-legacy-dithering.patch"
+
     # Sanity-check the patches landed.
     grep -q "KHR_robustness2 = true," src/panfrost/vulkan/panvk_vX_physical_device.c
     grep -q "EXT_robustness2 = true," src/panfrost/vulkan/panvk_vX_physical_device.c
@@ -138,6 +163,11 @@ prepare() {
     test -f src/panfrost/vulkan/jm/panvk_vX_cmd_xfb.c
     # iter17 sanity: pan_nir_lower_xfb call site has been replaced; new file present.
     grep -q "panvk_per_arch(nir_lower_xfb)" src/panfrost/vulkan/panvk_vX_shader.c
+    # r5 sanity: fragmentStoresAndAtomics = true patch landed
+    grep -q "fragmentStoresAndAtomics = true ||" src/panfrost/vulkan/panvk_vX_physical_device.c
+    # r6 sanity: VK_EXT_legacy_dithering advertised
+    grep -q '\.EXT_legacy_dithering = true,' src/panfrost/vulkan/panvk_vX_physical_device.c
+    grep -q '\.legacyDithering = true,' src/panfrost/vulkan/panvk_vX_physical_device.c
     grep -q "xfb_topology" src/panfrost/vulkan/panvk_shader.h
     grep -q "panvk_xfb_topology" src/panfrost/vulkan/panvk_shader.h
     test -f src/panfrost/vulkan/panvk_vX_xfb_lower.c

debian/chromium-fourier/build-deb.sh

@@ -0,0 +1,150 @@
+#!/bin/bash
+# Package pre-built chromium-fourier artifacts into a .deb.
+#
+# Chromium can't be compiled natively on any available aarch64 runner
+# (clang version wall — chromium requires its internal clang fork).
+# The build is cross-compiled on CT 220 (data, x86_64 Ryzen 7).
+# This script expects the build artifacts to exist at BUILD_DIR
+# (default: fetched from CT 220 via SSH).
+#
+# Sibling Arch package: ../../arch/chromium-fourier/PKGBUILD
+set -euo pipefail
+
+PKGVER=148.0.7778.178
+EPOCH=1
+PKGREL=1
+ARCH=arm64
+
+HERE=$(dirname "$(readlink -f "$0")")
+export SOURCE_DATE_EPOCH=1779854400  # 2026-05-24 09:00 UTC
+
+BUILD_DIR="${BUILD_DIR:-}"
+
+work=$(mktemp -d)
+trap "rm -rf $work" EXIT
+
+if [ -z "$BUILD_DIR" ]; then
+    echo "BUILD_DIR not set — fetching artifacts from CT 220 on data..."
+    BUILD_DIR="$work/artifacts"
+    mkdir -p "$BUILD_DIR"
+    ssh root@data "pct exec 220 -- tar -cf - -C /build/chromium/src/out/Default \
+        chrome chrome_crashpad_handler \
+        libEGL.so libGLESv2.so libvk_swiftshader.so libvulkan.so.1 \
+        vk_swiftshader_icd.json \
+        chrome_100_percent.pak chrome_200_percent.pak resources.pak \
+        v8_context_snapshot.bin snapshot_blob.bin icudtl.dat \
+        locales/" | tar -xf - -C "$BUILD_DIR"
+fi
+
+ROOT="$work/pkgroot"
+
+install -Dm755 "$BUILD_DIR/chrome"                   "$ROOT/usr/lib/chromium/chromium"
+install -Dm755 "$BUILD_DIR/chrome_crashpad_handler"  "$ROOT/usr/lib/chromium/chrome_crashpad_handler"
+
+for so in libEGL.so libGLESv2.so libvk_swiftshader.so libvulkan.so.1; do
+    [ -f "$BUILD_DIR/$so" ] && install -Dm755 "$BUILD_DIR/$so" "$ROOT/usr/lib/chromium/$so"
+done
+
+for icd in "$BUILD_DIR"/*_icd.json; do
+    [ -f "$icd" ] && install -Dm644 "$icd" "$ROOT/usr/lib/chromium/$(basename "$icd")"
+done
+
+for f in chrome_100_percent.pak chrome_200_percent.pak resources.pak \
+         v8_context_snapshot.bin snapshot_blob.bin icudtl.dat; do
+    [ -f "$BUILD_DIR/$f" ] && install -Dm644 "$BUILD_DIR/$f" "$ROOT/usr/lib/chromium/$f"
+done
+
+if [ -d "$BUILD_DIR/locales" ]; then
+    install -dm755 "$ROOT/usr/lib/chromium/locales"
+    cp -r "$BUILD_DIR/locales/"* "$ROOT/usr/lib/chromium/locales/"
+fi
+
+install -dm755 "$ROOT/usr/bin"
+cat > "$ROOT/usr/bin/chromium-fourier" <<'LAUNCHER'
+#!/bin/bash
+USER_HANDLES_VULKAN=0
+for arg in "$@"; do
+  case "$arg" in
+    --use-vulkan*|--enable-features=*Vulkan*|--disable-features=*Vulkan*|--use-angle=vulkan*)
+      USER_HANDLES_VULKAN=1
+      break
+      ;;
+  esac
+done
+
+vulkan_default=()
+if [ "$USER_HANDLES_VULKAN" = 0 ]; then
+  vulkan_default=(--disable-features=Vulkan)
+fi
+
+exec /usr/lib/chromium/chromium \
+  --ozone-platform=wayland \
+  --use-gl=angle --use-angle=gles \
+  --enable-features=AcceleratedVideoDecoder \
+  "${vulkan_default[@]}" \
+  "$@"
+LAUNCHER
+chmod 0755 "$ROOT/usr/bin/chromium-fourier"
+
+mkdir -p "$ROOT/usr/share/doc/chromium-fourier" "$ROOT/DEBIAN"
+install -Dm644 "$HERE/debian/copyright" \
+    "$ROOT/usr/share/doc/chromium-fourier/copyright"
+install -Dm644 "$HERE/debian/changelog" \
+    "$ROOT/usr/share/doc/chromium-fourier/changelog.Debian"
+gzip -9 -n "$ROOT/usr/share/doc/chromium-fourier/changelog.Debian"
+
+ISIZE=$(du -sk "$ROOT" | awk '{print $1}')
+cat > "$ROOT/DEBIAN/control" <<EOF
+Package: chromium-fourier
+Version: ${EPOCH}:${PKGVER}-${PKGREL}
+Section: web
+Priority: optional
+Architecture: ${ARCH}
+Installed-Size: ${ISIZE}
+Depends: libasound2,
+         libatk-bridge2.0-0,
+         libatk1.0-0,
+         libcairo2,
+         libcups2,
+         libdbus-1-3,
+         libdrm2,
+         libexpat1,
+         libfontconfig1,
+         libfreetype6,
+         libgbm1,
+         libglib2.0-0,
+         libgtk-3-0,
+         libnspr4,
+         libnss3,
+         libpango-1.0-0,
+         libpulse0,
+         libva2,
+         libwayland-client0,
+         libx11-6,
+         libxcb1,
+         libxkbcommon0,
+         libpipewire-0.3-0,
+         fonts-liberation,
+         v4l-utils
+Provides: www-browser
+Conflicts: chromium
+Maintainer: Markus Fritsche <mfritsche@reauktion.de>
+Homepage: https://www.chromium.org/
+Description: Chromium with V4L2 HW video decode for Rockchip (Wayland + mainline)
+ Chromium ${PKGVER} with three patches enabling V4L2 hardware video
+ decoding on mainline Linux / Wayland for Rockchip SoCs (RK3566 hantro,
+ RK3588 VDPU381).
+ .
+ Cross-compiled from x86_64 using chromium's bundled clang (upstream
+ LLVM cannot compile chromium). Runtime target is aarch64.
+ .
+ Patches: enable-v4l2-decoder-default, wayland-allow-direct-egl-gles2,
+ nv12-external-oes-on-modifier-external-only.
+ .
+ Launcher at /usr/bin/chromium-fourier defaults to Wayland + ANGLE/GLES
+ with Vulkan disabled (panvk on RK3566 breaks V4L2 dispatch).
+EOF
+
+DEB_OUT="chromium-fourier_${EPOCH}%3a${PKGVER}-${PKGREL}_${ARCH}.deb"
+dpkg-deb --root-owner-group --build "$ROOT" "$HERE/$DEB_OUT"
+echo "built: $HERE/$DEB_OUT"

debian/chromium-fourier/debian/changelog

@@ -0,0 +1,8 @@
+chromium-fourier (1:148.0.7778.178-1) trixie; urgency=medium
+
+  * Chromium 148.0.7778.178 with V4L2 HW decode patches for Rockchip.
+  * Cross-compiled from x86_64 using chromium's bundled clang.
+  * Three fourier patches: enable-v4l2-decoder-default,
+    wayland-allow-direct-egl-gles2, nv12-external-oes-on-modifier-external-only.
+
+ -- Markus Fritsche <mfritsche@reauktion.de>  Sat, 24 May 2026 09:00:00 +0200

debian/chromium-fourier/debian/copyright

@@ -0,0 +1,32 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: Chromium
+Upstream-Contact: chromium-dev@chromium.org
+Source: https://www.chromium.org/
+
+Files: *
+Copyright: The Chromium Authors
+License: BSD-3-Clause
+
+Files: debian/*
+Copyright: 2026 Markus Fritsche <mfritsche@reauktion.de>
+License: BSD-3-Clause
+
+License: BSD-3-Clause
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+ .
+ 1. Redistributions of source code must retain the above copyright notice,
+    this list of conditions and the following disclaimer.
+ .
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ .
+ 3. Neither the name of the copyright holder nor the names of its
+    contributors may be used to endorse or promote products derived from
+    this software without specific prior written permission.
+ .
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ ARE DISCLAIMED.