marfrit
489d6e3862
iter9 of the panvk-bifrost campaign — operator-confirmed Vulkan output
on PineTab2 (Mali-G52 r1 MC1) 2026-05-20.
Patches Mesa 26.0.6's PanVk Vulkan driver:
- VK_KHR/EXT_robustness2 + nullDescriptor exposed for PAN_ARCH 6/7
- has_vk1_1 / has_vk1_2 = true on Bifrost
Patches applied via sed in PKGBUILD prepare() (cleaner than maintaining
a Mesa fork for two two-line tweaks; upstream context drifts between
Mesa releases would make a literal .patch brittle).
Co-installs at /usr/lib/panvk-bifrost/ — stock mesa untouched. Stock
libvulkan_panfrost.so and its ICD JSON keep working for everyone not
opting into the patched driver.
Ships /usr/bin/brave-vulkan that wires up:
VK_ICD_FILENAMES=/usr/lib/panvk-bifrost/icd.json
PAN_I_WANT_A_BROKEN_VULKAN_DRIVER=1
MESA_VK_VERSION_OVERRIDE=1.2 # ANGLE needs apiVersion>=1.1; the
# has_vk1_x flags don't move it, so
# the env-var override carries that
brave --use-gl=disabled --enable-features=Vulkan --use-vulkan=native
--ozone-platform=x11 --no-sandbox --disable-gpu-sandbox
--ignore-gpu-blocklist "$@"
Side-steps the stock "GLES3 is unsupported / GPU process exits" failure
documented in panvk-bifrost/README's "Consumer-side benefit" section.
Known limitation: WebGL/WebGL2 in-page won't work — ANGLE needs GLES3
which needs VK_EXT_transform_feedback, which PanVk-Bifrost doesn't
currently support. Browser chrome + standard page rendering work fine.
Gitea Actions job mesa-panvk-bifrost-aarch64 added to build.yml,
patterned on libva-v4l2-request-fourier-aarch64. Mesa build is slow
(~30-60min on actrunner-aarch64). Standalone (no needs:),
continue-on-error so it doesn't block other jobs.
Campaign artifacts: ~/src/panvk-bifrost/{README.md, phase8_iteration9_close.md,
phase0_evidence/iter9_brave_vulkan_breakthrough.txt}.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
58 lines
2.6 KiB
Diff
58 lines
2.6 KiB
Diff
From: claude-noether (on behalf of mfritsche)
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Date: 2026-05-19
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Subject: panvk: expose VK_KHR/EXT_robustness2 + nullDescriptor on Bifrost (PAN_ARCH 6/7)
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Without this, Mesa's Zink driver refuses to use PanVk-Bifrost as its Vulkan
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backend, falling back silently to llvmpipe (software rasterizer) for all
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GL-via-Zink on Bifrost SBCs. That defeats the entire purpose of having a
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Vulkan driver on Bifrost — GL acceleration via Zink is the most natural
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near-term consumer.
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panvk_vX_nir_lower_descriptors.c:1309 and panvk_vX_shader.c:1355 already
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plumb dev->vk.enabled_features.nullDescriptor arch-agnostically — the gate
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at panvk_vX_physical_device.c was set conservatively when Bifrost was
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unmaintained, not because of hardware incapability.
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iter1–7 of the panvk-bifrost campaign proved fundamental driver functions
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on Mali-G52 r1 MC1 (PAN_ARCH=7). This patch is the iter8 follow-up.
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robustBufferAccess2 and robustImageAccess2 are NOT flipped — they're
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independent rb2 features Zink doesn't require, gated differently
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(robustBufferAccess2 = PAN_ARCH >= 11, robustImageAccess2 = false), and
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out of scope for iter8.
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---
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src/panfrost/vulkan/panvk_vX_physical_device.c | 6 +++---
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1 file changed, 3 insertions(+), 3 deletions(-)
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diff --git a/src/panfrost/vulkan/panvk_vX_physical_device.c b/src/panfrost/vulkan/panvk_vX_physical_device.c
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--- a/src/panfrost/vulkan/panvk_vX_physical_device.c
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+++ b/src/panfrost/vulkan/panvk_vX_physical_device.c
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@@ -91,7 +91,7 @@ get_device_extensions(const struct panvk_physical_device *device,
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.KHR_pipeline_binary = true,
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.KHR_pipeline_executable_properties = true,
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.KHR_pipeline_library = true,
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- .KHR_robustness2 = PAN_ARCH >= 10,
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+ .KHR_robustness2 = true,
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.KHR_sampler_mirror_clamp_to_edge = true,
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.KHR_sampler_ycbcr_conversion = true,
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.KHR_separate_depth_stencil_layouts = true,
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@@ -168,7 +168,7 @@ get_device_extensions(const struct panvk_physical_device *device,
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.EXT_queue_family_foreign = true,
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.EXT_robustness = pan_arch(device->kmod.dev->props.gpu_id) >= 9,
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.EXT_image_robustness = true,
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- .EXT_robustness2 = PAN_ARCH >= 10,
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+ .EXT_robustness2 = true,
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.EXT_sampler_filter_minmax = PAN_ARCH >= 10,
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.EXT_scalar_block_layout = true,
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.EXT_separate_stencil_usage = true,
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@@ -493,7 +493,7 @@ get_device_features(const struct panvk_physical_device *device,
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/* VK_KHR_robustness2 */
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.robustBufferAccess2 = PAN_ARCH >= 11,
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.robustImageAccess2 = false,
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- .nullDescriptor = PAN_ARCH >= 10,
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+ .nullDescriptor = true,
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/* VK_KHR_shader_clock */
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.shaderSubgroupClock = device->kmod.dev->props.gpu_can_query_timestamp,
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