From: claude-noether (on behalf of mfritsche)
Date: 2026-05-19
Subject: panvk: expose VK_KHR/EXT_robustness2 + nullDescriptor on Bifrost (PAN_ARCH 6/7)

Without this, Mesa's Zink driver refuses to use PanVk-Bifrost as its Vulkan
backend, falling back silently to llvmpipe (software rasterizer) for all
GL-via-Zink on Bifrost SBCs. That defeats the entire purpose of having a
Vulkan driver on Bifrost — GL acceleration via Zink is the most natural
near-term consumer.

panvk_vX_nir_lower_descriptors.c:1309 and panvk_vX_shader.c:1355 already
plumb dev->vk.enabled_features.nullDescriptor arch-agnostically — the gate
at panvk_vX_physical_device.c was set conservatively when Bifrost was
unmaintained, not because of hardware incapability.

iter1–7 of the panvk-bifrost campaign proved fundamental driver functions
on Mali-G52 r1 MC1 (PAN_ARCH=7). This patch is the iter8 follow-up.

robustBufferAccess2 and robustImageAccess2 are NOT flipped — they're
independent rb2 features Zink doesn't require, gated differently
(robustBufferAccess2 = PAN_ARCH >= 11, robustImageAccess2 = false), and
out of scope for iter8.

---
 src/panfrost/vulkan/panvk_vX_physical_device.c | 6 +++---
 1 file changed, 3 insertions(+), 3 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
@@ -91,7 +91,7 @@ get_device_extensions(const struct panvk_physical_device *device,
       .KHR_pipeline_binary = true,
       .KHR_pipeline_executable_properties = true,
       .KHR_pipeline_library = true,
-      .KHR_robustness2 = PAN_ARCH >= 10,
+      .KHR_robustness2 = true,
       .KHR_sampler_mirror_clamp_to_edge = true,
       .KHR_sampler_ycbcr_conversion = true,
       .KHR_separate_depth_stencil_layouts = true,
@@ -168,7 +168,7 @@ get_device_extensions(const struct panvk_physical_device *device,
       .EXT_queue_family_foreign = true,
       .EXT_robustness = pan_arch(device->kmod.dev->props.gpu_id) >= 9,
       .EXT_image_robustness = true,
-      .EXT_robustness2 = PAN_ARCH >= 10,
+      .EXT_robustness2 = true,
       .EXT_sampler_filter_minmax = PAN_ARCH >= 10,
       .EXT_scalar_block_layout = true,
       .EXT_separate_stencil_usage = true,
@@ -493,7 +493,7 @@ get_device_features(const struct panvk_physical_device *device,
       /* VK_KHR_robustness2 */
       .robustBufferAccess2 = PAN_ARCH >= 11,
       .robustImageAccess2 = false,
-      .nullDescriptor = PAN_ARCH >= 10,
+      .nullDescriptor = true,

       /* VK_KHR_shader_clock */
       .shaderSubgroupClock = device->kmod.dev->props.gpu_can_query_timestamp,