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Merge pull request 'mesa-panvk-bifrost-video: r1-r4 patches as real files (symlinks broke CI)' (#83) from claude-noether/marfrit-packages:noether/mesa-panvk-bifrost-video-retrigger into main

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Reviewed-on: marfrit/marfrit-packages#83
This commit is contained in:
Markus Fritsche
2026-05-22 07:55:59 +00:00
parent 6288536223 4db64917bc
commit 360e8eb6bf
4 changed files with 1061 additions and 4 deletions
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arch/mesa-panvk-bifrost-video/0001-panvk-expose-robustness2-nullDescriptor-bifrost.patch
-1
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@@ -1 +0,0 @@
../mesa-panvk-bifrost/0001-panvk-expose-robustness2-nullDescriptor-bifrost.patch
arch/mesa-panvk-bifrost-video/0001-panvk-expose-robustness2-nullDescriptor-bifrost.patch
+57
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@@ -0,0 +1,57 @@
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,
arch/mesa-panvk-bifrost-video/0002-panvk-expose-vulkan-1.1-1.2-on-bifrost.patch
-1
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@@ -1 +0,0 @@
../mesa-panvk-bifrost/0002-panvk-expose-vulkan-1.1-1.2-on-bifrost.patch
arch/mesa-panvk-bifrost-video/0002-panvk-expose-vulkan-1.1-1.2-on-bifrost.patch
+47
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@@ -0,0 +1,47 @@
From: claude-noether (on behalf of mfritsche)
Date: 2026-05-20
Subject: panvk: expose Vulkan 1.1 + 1.2 on Bifrost (PAN_ARCH 6/7)
ANGLE (Chromium's GL stack) requires apiVersion >= 1.1 to initialize. Without
this, Brave / Chromium's GPU process fails at GL info collection:
vk_renderer.cpp:2659 (initialize): ANGLE Requires a minimum Vulkan device
version of 1.1
Display::initialize error 0: Internal Vulkan error (-9): The requested
version of Vulkan is not supported by the driver
Stack-up with iter8's robustness2 patch enables ANGLE → PanVk-Bifrost →
Skia (via --enable-features=Vulkan) on Bifrost SBCs.
PanVk-Bifrost already supports the bulk of 1.1-promoted features as extensions
(multiview, maintenance1-3, descriptor update template, 16-bit storage,
descriptor update template, sampler ycbcr, variable pointers, etc. — all
visible in iter0 vulkaninfo). The version bump primarily bundles them.
Risk: Vulkan 1.1 has features beyond what iter1–7 exercised (protected memory,
full subgroup ops). Specific app failures will be characterizable.
1.2 is also flipped — Brave's Vulkan path may want descriptor indexing,
buffer device address, etc. (all listed in iter0 vulkaninfo as supported
extensions, just gated as 1.0-with-extensions, not 1.2-core).
---
src/panfrost/vulkan/panvk_vX_physical_device.c | 4 ++--
1 file changed, 2 insertions(+), 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
@@ -38,8 +38,8 @@ get_device_extensions(const struct panvk_physical_device *device,
struct vk_device_extension_table *ext)
{
*ext = (struct vk_device_extension_table){
- .KHR_8bit_storage = true,
- .KHR_16bit_storage = true,
- bool has_vk1_1 = PAN_ARCH >= 10;
- bool has_vk1_2 = PAN_ARCH >= 10;
+ .KHR_8bit_storage = true,
+ .KHR_16bit_storage = true,
+ bool has_vk1_1 = true;
+ bool has_vk1_2 = true;
*ext = (struct vk_device_extension_table){
arch/mesa-panvk-bifrost-video/0003-panvk-bifrost-vk-ext-transform-feedback.patch
-1
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@@ -1 +0,0 @@
../mesa-panvk-bifrost/0003-panvk-bifrost-vk-ext-transform-feedback.patch
arch/mesa-panvk-bifrost-video/0003-panvk-bifrost-vk-ext-transform-feedback.patch
+328
View File
@@ -0,0 +1,328 @@
--- a/src/panfrost/vulkan/panvk_shader.h 2026-04-29 22:19:00.000000000 +0200
+++ b/src/panfrost/vulkan/panvk_shader.h 2026-05-20 18:52:53.312698258 +0200
@@ -150,6 +150,10 @@
struct {
#if PAN_ARCH < 9
int32_t raw_vertex_offset;
+ uint32_t num_vertices; /* iter13: XFB needs per-draw vertex count */
+ /* aligned_u64 attribute below inserts the 4-byte alignment gap
+ * after num_vertices automatically — no explicit pad needed. */
+ aligned_u64 xfb_address[4]; /* iter13: 4 transform feedback buffer base addresses */
#endif
int32_t first_vertex;
int32_t base_instance;
--- a/src/panfrost/vulkan/panvk_vX_physical_device.c 2026-05-20 19:09:29.711145446 +0200
+++ b/src/panfrost/vulkan/panvk_vX_physical_device.c 2026-05-20 18:52:54.832720445 +0200
@@ -169,6 +169,7 @@
.EXT_provoking_vertex = true,
.EXT_queue_family_foreign = true,
.EXT_robustness2 = true,
+ .EXT_transform_feedback = PAN_ARCH < 9, /* iter13: JM-class only for now */
.EXT_sampler_filter_minmax = PAN_ARCH >= 10,
.EXT_scalar_block_layout = true,
.EXT_separate_stencil_usage = true,
@@ -495,6 +496,10 @@
.robustImageAccess2 = false,
.nullDescriptor = true,
+ /* VK_EXT_transform_feedback (iter13) */
+ .transformFeedback = PAN_ARCH < 9,
+ .geometryStreams = false,
+
/* VK_KHR_shader_clock */
.shaderSubgroupClock = device->kmod.dev->props.gpu_can_query_timestamp,
.shaderDeviceClock = device->kmod.dev->props.timestamp_device_coherent,
@@ -1020,6 +1025,18 @@
.robustStorageBufferAccessSizeAlignment = 1,
.robustUniformBufferAccessSizeAlignment = 1,
+ /* VK_EXT_transform_feedback (iter13) */
+ .maxTransformFeedbackStreams = 1,
+ .maxTransformFeedbackBuffers = 4,
+ .maxTransformFeedbackBufferSize = UINT32_MAX,
+ .maxTransformFeedbackStreamDataSize = 512,
+ .maxTransformFeedbackBufferDataSize = 512,
+ .maxTransformFeedbackBufferDataStride = 2048,
+ .transformFeedbackQueries = false,
+ .transformFeedbackStreamsLinesTriangles = false,
+ .transformFeedbackRasterizationStreamSelect = false,
+ .transformFeedbackDraw = false,
+
/* VK_EXT_shader_object */
/* We do not currently support VK_EXT_shader_object but this is used
* internally by vk_shader
--- a/src/panfrost/vulkan/panvk_vX_shader.c 2026-04-29 22:19:00.000000000 +0200
+++ b/src/panfrost/vulkan/panvk_vX_shader.c 2026-05-20 18:52:56.556745611 +0200
@@ -21,6 +21,7 @@
#include "panvk_physical_device.h"
#include "panvk_sampler.h"
#include "panvk_shader.h"
+#include "pan_nir.h" /* iter13: pan_nir_lower_xfb */
#include "spirv/nir_spirv.h"
#include "util/memstream.h"
@@ -100,6 +101,20 @@
case nir_intrinsic_load_raw_vertex_offset_pan:
val = load_sysval(b, graphics, bit_size, vs.raw_vertex_offset);
break;
+ case nir_intrinsic_load_num_vertices: /* iter13: XFB index calc */
+ val = load_sysval(b, graphics, bit_size, vs.num_vertices);
+ break;
+ case nir_intrinsic_load_xfb_address: { /* iter13: XFB buffer N base address */
+ unsigned idx = nir_intrinsic_base(intr);
+ switch (idx) {
+ case 0: val = load_sysval(b, graphics, bit_size, vs.xfb_address[0]); break;
+ case 1: val = load_sysval(b, graphics, bit_size, vs.xfb_address[1]); break;
+ case 2: val = load_sysval(b, graphics, bit_size, vs.xfb_address[2]); break;
+ case 3: val = load_sysval(b, graphics, bit_size, vs.xfb_address[3]); break;
+ default: return false;
+ }
+ break;
+ }
case nir_intrinsic_load_layer_id:
assert(b->shader->info.stage == MESA_SHADER_FRAGMENT);
val = load_sysval(b, graphics, bit_size, layer_id);
@@ -457,6 +472,7 @@
core_max_id);
pan_preprocess_nir(nir, pdev->kmod.dev->props.gpu_id);
+
}
static void
@@ -870,6 +886,18 @@
nir_var_shader_in | nir_var_shader_out, UINT32_MAX);
NIR_PASS(_, nir, nir_lower_io, nir_var_shader_in | nir_var_shader_out,
glsl_type_size, nir_lower_io_use_interpolated_input_intrinsics);
+
+#if PAN_ARCH < 9
+ /* iter13: VK_EXT_transform_feedback — runs AFTER nir_lower_io so that
+ * shader outputs are now store_output intrinsics that pan_nir_lower_xfb
+ * can rewrite to nir_store_global+nir_load_xfb_address. */
+ if (nir->info.stage == MESA_SHADER_VERTEX &&
+ nir->info.has_transform_feedback_varyings) {
+ NIR_PASS(_, nir, nir_opt_constant_folding);
+ NIR_PASS(_, nir, nir_io_add_intrinsic_xfb_info);
+ NIR_PASS(_, nir, pan_nir_lower_xfb);
+ }
+#endif
}
static VkResult
@@ -1288,6 +1316,9 @@
.view_mask = (state && state->rp) ? state->rp->view_mask : 0,
.robust2_modes = robust2_modes,
.robust_descriptors = dev->vk.enabled_features.nullDescriptor,
+ /* iter13: XFB shaders must disable IDVS (matches Panfrost-Gallium). */
+ .no_idvs = (info->stage == MESA_SHADER_VERTEX) &&
+ info->nir->info.has_transform_feedback_varyings,
};
switch (info->stage) {
--- a/src/panfrost/vulkan/panvk_cmd_draw.h 2026-04-29 22:19:00.000000000 +0200
+++ b/src/panfrost/vulkan/panvk_cmd_draw.h 2026-05-20 18:52:57.748763011 +0200
@@ -135,6 +135,19 @@
struct panvk_graphics_sysvals sysvals;
#if PAN_ARCH < 9
+ /* iter13: VK_EXT_transform_feedback state (JM-class only for now). */
+ struct {
+ bool active;
+ uint32_t buffer_count;
+ struct {
+ uint64_t addr;
+ uint64_t offset;
+ uint64_t size;
+ } buffers[4];
+ } xfb;
+#endif
+
+#if PAN_ARCH < 9
struct panvk_shader_link link;
#endif
--- a/src/panfrost/vulkan/panvk_vX_cmd_draw.c 2026-04-29 22:19:00.000000000 +0200
+++ b/src/panfrost/vulkan/panvk_vX_cmd_draw.c 2026-05-20 19:10:23.031919662 +0200
@@ -10,6 +10,7 @@
#include "panvk_entrypoints.h"
#include "pan_desc.h"
+#include "pan_compiler.h" /* PAN_SHADER_OOB_ADDRESS */
#include "pan_util.h"
static void
@@ -722,6 +723,35 @@
set_gfx_sysval(cmdbuf, dirty_sysvals, vs.raw_vertex_offset,
info->vertex.raw_offset);
set_gfx_sysval(cmdbuf, dirty_sysvals, layer_id, info->layer_id);
+
+ /* iter13: VK_EXT_transform_feedback sysvals — always set (per draw),
+ * reflect bound XFB state. set_gfx_sysval is a no-op if value unchanged. */
+ set_gfx_sysval(cmdbuf, dirty_sysvals, vs.num_vertices, info->vertex.count);
+ {
+ const struct panvk_cmd_graphics_state *_gfx = &cmdbuf->state.gfx;
+ /* iter13: default each XFB buffer address to PAN_SHADER_OOB_ADDRESS
+ * (= 1<<63). This is the Panfrost-Gallium memory-sink idiom — the
+ * Bifrost MMU silently discards stores to this address, so a pipeline
+ * with XFB outputs used in a non-XFB draw (or in an XFB draw with
+ * fewer bound buffers than the shader declares) is safe instead of
+ * faulting. See gallium/drivers/panfrost/pan_cmdstream.c PAN_SYSVAL_XFB. */
+ uint64_t _xa0 = PAN_SHADER_OOB_ADDRESS, _xa1 = PAN_SHADER_OOB_ADDRESS,
+ _xa2 = PAN_SHADER_OOB_ADDRESS, _xa3 = PAN_SHADER_OOB_ADDRESS;
+ if (_gfx->xfb.active) {
+ if (_gfx->xfb.buffer_count > 0 && _gfx->xfb.buffers[0].addr)
+ _xa0 = _gfx->xfb.buffers[0].addr + _gfx->xfb.buffers[0].offset;
+ if (_gfx->xfb.buffer_count > 1 && _gfx->xfb.buffers[1].addr)
+ _xa1 = _gfx->xfb.buffers[1].addr + _gfx->xfb.buffers[1].offset;
+ if (_gfx->xfb.buffer_count > 2 && _gfx->xfb.buffers[2].addr)
+ _xa2 = _gfx->xfb.buffers[2].addr + _gfx->xfb.buffers[2].offset;
+ if (_gfx->xfb.buffer_count > 3 && _gfx->xfb.buffers[3].addr)
+ _xa3 = _gfx->xfb.buffers[3].addr + _gfx->xfb.buffers[3].offset;
+ }
+ set_gfx_sysval(cmdbuf, dirty_sysvals, vs.xfb_address[0], _xa0);
+ set_gfx_sysval(cmdbuf, dirty_sysvals, vs.xfb_address[1], _xa1);
+ set_gfx_sysval(cmdbuf, dirty_sysvals, vs.xfb_address[2], _xa2);
+ set_gfx_sysval(cmdbuf, dirty_sysvals, vs.xfb_address[3], _xa3);
+ }
#endif
if (dyn_gfx_state_dirty(cmdbuf, CB_BLEND_CONSTANTS)) {
--- a/src/panfrost/vulkan/meson.build 2026-04-29 22:19:00.000000000 +0200
+++ b/src/panfrost/vulkan/meson.build 2026-05-20 18:53:04.484861338 +0200
@@ -73,6 +73,7 @@
jm_inc_dir = ['jm']
jm_files = [
'jm/panvk_vX_bind_queue.c',
+ 'jm/panvk_vX_cmd_xfb.c', # iter13
'jm/panvk_vX_cmd_buffer.c',
'jm/panvk_vX_cmd_dispatch.c',
'jm/panvk_vX_cmd_draw.c',
--- a/src/panfrost/vulkan/jm/panvk_vX_cmd_buffer.c 2026-04-29 22:19:00.000000000 +0200
+++ b/src/panfrost/vulkan/jm/panvk_vX_cmd_buffer.c 2026-05-20 19:10:26.163965149 +0200
@@ -473,5 +473,12 @@
vk_command_buffer_begin(&cmdbuf->vk, pBeginInfo);
+#if PAN_ARCH < 9
+ /* iter13: clear XFB state on Begin so a reused command buffer does not
+ * inherit stale xfb.buffer_count / xfb.active / xfb.buffers[] from a
+ * prior recording. */
+ memset(&cmdbuf->state.gfx.xfb, 0, sizeof(cmdbuf->state.gfx.xfb));
+#endif
+
return VK_SUCCESS;
}
--- a/src/panfrost/vulkan/jm/panvk_vX_cmd_xfb.c 2026-05-18 12:50:53.067999996 +0200
+++ b/src/panfrost/vulkan/jm/panvk_vX_cmd_xfb.c 2026-05-20 19:10:27.175979847 +0200
@@ -0,0 +1,111 @@
+/*
+ * Copyright © 2026 mfritsche / claude-noether
+ * SPDX-License-Identifier: MIT
+ *
+ * iter13: VK_EXT_transform_feedback command handlers for the JM
+ * architecture path (Bifrost v6/v7 + Valhall-JM v9).
+ *
+ * The runtime contract:
+ * - vkCmdBindTransformFeedbackBuffersEXT: stash (gpu_addr, offset, size)
+ * for each slot into cmdbuf->state.gfx.xfb.buffers[].
+ * - vkCmdBeginTransformFeedbackEXT: set cmdbuf->state.gfx.xfb.active = true.
+ * Mark sysvals dirty so the next draw re-emits vs.xfb_address[].
+ * - vkCmdEndTransformFeedbackEXT: set active = false.
+ *
+ * Counter buffers (firstCounterBuffer/counterBufferCount/pCounterBuffers/
+ * pCounterBufferOffsets) are accepted by API but ignored — v1 doesn't
+ * support pause/resume. transformFeedbackDraw is advertised as false.
+ *
+ * Per-draw integration: jm/panvk_vX_cmd_draw.c reads cmdbuf->state.gfx.xfb
+ * and populates vs.xfb_address[i] for shader use. The pan_nir_lower_xfb
+ * pass in panvk_vX_shader.c emits nir_load_xfb_address(i) which lowers
+ * (via panvk_vX_shader.c sysval handler) to a load from the per-draw
+ * sysval push area.
+ */
+
+#include "vk_log.h"
+#include "util/log.h"
+
+#include "panvk_cmd_buffer.h"
+#include "panvk_cmd_draw.h"
+#include "panvk_buffer.h"
+#include "panvk_entrypoints.h"
+
+VKAPI_ATTR void VKAPI_CALL
+panvk_per_arch(CmdBindTransformFeedbackBuffersEXT)(
+ VkCommandBuffer commandBuffer,
+ uint32_t firstBinding,
+ uint32_t bindingCount,
+ const VkBuffer *pBuffers,
+ const VkDeviceSize *pOffsets,
+ const VkDeviceSize *pSizes)
+{
+ VK_FROM_HANDLE(panvk_cmd_buffer, cmdbuf, commandBuffer);
+ struct panvk_cmd_graphics_state *gfx = &cmdbuf->state.gfx;
+
+ for (uint32_t i = 0; i < bindingCount; i++) {
+ uint32_t slot = firstBinding + i;
+ if (slot >= 4)
+ continue;
+
+ VK_FROM_HANDLE(panvk_buffer, buf, pBuffers[i]);
+ gfx->xfb.buffers[slot].addr = panvk_buffer_gpu_ptr(buf, 0);
+ gfx->xfb.buffers[slot].offset = pOffsets[i];
+ gfx->xfb.buffers[slot].size =
+ (pSizes != NULL && pSizes[i] != VK_WHOLE_SIZE)
+ ? pSizes[i]
+ : (buf->vk.size - pOffsets[i]);
+ }
+
+ if (firstBinding + bindingCount > gfx->xfb.buffer_count)
+ gfx->xfb.buffer_count = firstBinding + bindingCount;
+}
+
+VKAPI_ATTR void VKAPI_CALL
+panvk_per_arch(CmdBeginTransformFeedbackEXT)(
+ VkCommandBuffer commandBuffer,
+ uint32_t firstCounterBuffer,
+ uint32_t counterBufferCount,
+ const VkBuffer *pCounterBuffers,
+ const VkDeviceSize *pCounterBufferOffsets)
+{
+ VK_FROM_HANDLE(panvk_cmd_buffer, cmdbuf, commandBuffer);
+ struct panvk_cmd_graphics_state *gfx = &cmdbuf->state.gfx;
+
+ /* Counter buffers ignored in v1 — see VkPhysicalDeviceTransformFeedback
+ * PropertiesEXT.transformFeedbackDraw = false in panvk_vX_physical_device.c.
+ * App is spec-compliant if it does not pass counter buffers (which our
+ * features advertisement allows), but warn loudly if it does so we do not
+ * silently produce wrong capture state. */
+ (void)firstCounterBuffer;
+ (void)pCounterBufferOffsets;
+ if (counterBufferCount > 0 && pCounterBuffers != NULL) {
+ mesa_logw("panvk: CmdBeginTransformFeedbackEXT: counter buffers not "
+ "implemented (transformFeedbackDraw=false); XFB resume will "
+ "restart at buffer offset 0");
+ }
+
+ gfx->xfb.active = true;
+ /* Per-draw set_gfx_sysval picks up the change automatically — no
+ * explicit dirty marking required (set_gfx_sysval uses memcmp +
+ * BITSET to detect state diffs and re-emit sysvals). */
+}
+
+VKAPI_ATTR void VKAPI_CALL
+panvk_per_arch(CmdEndTransformFeedbackEXT)(
+ VkCommandBuffer commandBuffer,
+ uint32_t firstCounterBuffer,
+ uint32_t counterBufferCount,
+ const VkBuffer *pCounterBuffers,
+ const VkDeviceSize *pCounterBufferOffsets)
+{
+ VK_FROM_HANDLE(panvk_cmd_buffer, cmdbuf, commandBuffer);
+ struct panvk_cmd_graphics_state *gfx = &cmdbuf->state.gfx;
+
+ (void)firstCounterBuffer;
+ (void)counterBufferCount;
+ (void)pCounterBuffers;
+ (void)pCounterBufferOffsets;
+
+ gfx->xfb.active = false;
+}
arch/mesa-panvk-bifrost-video/0004-panvk-bifrost-xfb-primitive-decomposition.patch
-1
View File
@@ -1 +0,0 @@
../mesa-panvk-bifrost/0004-panvk-bifrost-xfb-primitive-decomposition.patch
arch/mesa-panvk-bifrost-video/0004-panvk-bifrost-xfb-primitive-decomposition.patch
+629
View File
@@ -0,0 +1,629 @@
diff -urN a/src/panfrost/vulkan/meson.build b/src/panfrost/vulkan/meson.build
--- a/src/panfrost/vulkan/meson.build 2026-05-21 14:04:02.529474145 +0200
+++ b/src/panfrost/vulkan/meson.build 2026-05-21 14:04:04.106755486 +0200
@@ -123,6 +123,7 @@
'panvk_vX_nir_lower_input_attachment_loads.c',
'panvk_vX_sampler.c',
'panvk_vX_shader.c',
+ 'panvk_vX_xfb_lower.c',
sha1_h,
]
diff -urN a/src/panfrost/vulkan/panvk_shader.h b/src/panfrost/vulkan/panvk_shader.h
--- a/src/panfrost/vulkan/panvk_shader.h 2026-05-21 14:04:02.525251986 +0200
+++ b/src/panfrost/vulkan/panvk_shader.h 2026-05-21 14:04:04.084251800 +0200
@@ -154,6 +154,8 @@
/* aligned_u64 attribute below inserts the 4-byte alignment gap
* after num_vertices automatically — no explicit pad needed. */
aligned_u64 xfb_address[4]; /* iter13: 4 transform feedback buffer base addresses */
+ uint32_t xfb_topology; /* iter17: panvk_xfb_topology enum value */
+ uint32_t xfb_output_count; /* iter17: per-instance output verts after decomp */
#endif
int32_t first_vertex;
int32_t base_instance;
@@ -569,4 +571,76 @@
struct pan_compute_dim local_size, const void *bin_ptr, size_t bin_size,
struct panvk_shader **shader_out);
+
+#if PAN_ARCH < 9
+/* iter17: encoding for vs.xfb_topology sysval. Maps VkPrimitiveTopology values
+ * we need to distinguish at shader runtime for XFB capture. LIST topologies
+ * use the iter13 single-store fast path; non-LIST need per-vertex decomposition. */
+enum panvk_xfb_topology {
+ PANVK_XFB_TOPO_LIST = 0,
+ PANVK_XFB_TOPO_LINE_STRIP = 1,
+ PANVK_XFB_TOPO_TRI_STRIP = 2,
+ PANVK_XFB_TOPO_TRI_FAN = 3,
+ PANVK_XFB_TOPO_LINE_LIST_ADJ = 4,
+ PANVK_XFB_TOPO_LINE_STRIP_ADJ = 5,
+ PANVK_XFB_TOPO_TRI_LIST_ADJ = 6,
+ PANVK_XFB_TOPO_TRI_STRIP_ADJ = 7,
+};
+
+#include "panvk_macros.h"
+struct nir_shader;
+bool panvk_per_arch(nir_lower_xfb)(struct nir_shader *nir);
+
+/* Map VkPrimitiveTopology to panvk_xfb_topology enum (driver-side helper). */
+static inline uint32_t
+panvk_vk_topology_to_xfb_enum(VkPrimitiveTopology topo)
+{
+ switch (topo) {
+ case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP:
+ return PANVK_XFB_TOPO_LINE_STRIP;
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP:
+ return PANVK_XFB_TOPO_TRI_STRIP;
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN:
+ return PANVK_XFB_TOPO_TRI_FAN;
+ case VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY:
+ return PANVK_XFB_TOPO_LINE_LIST_ADJ;
+ case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY:
+ return PANVK_XFB_TOPO_LINE_STRIP_ADJ;
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY:
+ return PANVK_XFB_TOPO_TRI_LIST_ADJ;
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY:
+ return PANVK_XFB_TOPO_TRI_STRIP_ADJ;
+ case VK_PRIMITIVE_TOPOLOGY_POINT_LIST:
+ case VK_PRIMITIVE_TOPOLOGY_LINE_LIST:
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST:
+ default:
+ return PANVK_XFB_TOPO_LIST;
+ }
+}
+
+/* Compute the per-instance output vertex count for a given (topology, input count). */
+static inline uint32_t
+panvk_xfb_output_count(VkPrimitiveTopology topo, uint32_t input_count)
+{
+ switch (topo) {
+ case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP:
+ return input_count >= 1 ? 2u * (input_count - 1u) : 0u;
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP:
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_FAN:
+ return input_count >= 2 ? 3u * (input_count - 2u) : 0u;
+ case VK_PRIMITIVE_TOPOLOGY_LINE_LIST_WITH_ADJACENCY:
+ return (input_count / 4u) * 2u;
+ case VK_PRIMITIVE_TOPOLOGY_LINE_STRIP_WITH_ADJACENCY:
+ return input_count >= 3 ? 2u * (input_count - 3u) : 0u;
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY:
+ return (input_count / 6u) * 3u;
+ case VK_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP_WITH_ADJACENCY:
+ return input_count >= 6 ? 3u * (input_count / 2u - 2u) : 0u;
+ default:
+ return input_count; /* LIST topologies: 1:1 mapping */
+ }
+}
+#endif
+
+
#endif
diff -urN a/src/panfrost/vulkan/panvk_vX_cmd_draw.c b/src/panfrost/vulkan/panvk_vX_cmd_draw.c
--- a/src/panfrost/vulkan/panvk_vX_cmd_draw.c 2026-05-21 14:04:02.528576354 +0200
+++ b/src/panfrost/vulkan/panvk_vX_cmd_draw.c 2026-05-21 14:04:04.091357598 +0200
@@ -727,6 +727,20 @@
/* iter13: VK_EXT_transform_feedback sysvals — always set (per draw),
* reflect bound XFB state. set_gfx_sysval is a no-op if value unchanged. */
set_gfx_sysval(cmdbuf, dirty_sysvals, vs.num_vertices, info->vertex.count);
+
+ /* iter17: XFB primitive-decomposition sysvals.
+ * xfb_topology = enum value for the current bound topology.
+ * xfb_output_count = per-instance output vertex count after decomposition.
+ * For LIST topologies, output_count == input vertex count and the shader
+ * takes the iter13 single-store fast path. */
+ {
+ VkPrimitiveTopology vk_topo =
+ cmdbuf->vk.dynamic_graphics_state.ia.primitive_topology;
+ uint32_t topo_enum = panvk_vk_topology_to_xfb_enum(vk_topo);
+ uint32_t out_count = panvk_xfb_output_count(vk_topo, info->vertex.count);
+ set_gfx_sysval(cmdbuf, dirty_sysvals, vs.xfb_topology, topo_enum);
+ set_gfx_sysval(cmdbuf, dirty_sysvals, vs.xfb_output_count, out_count);
+ }
{
const struct panvk_cmd_graphics_state *_gfx = &cmdbuf->state.gfx;
/* iter13: default each XFB buffer address to PAN_SHADER_OOB_ADDRESS
diff -urN a/src/panfrost/vulkan/panvk_vX_shader.c b/src/panfrost/vulkan/panvk_vX_shader.c
--- a/src/panfrost/vulkan/panvk_vX_shader.c 2026-05-21 14:04:02.527576494 +0200
+++ b/src/panfrost/vulkan/panvk_vX_shader.c 2026-05-21 14:04:04.098356619 +0200
@@ -895,7 +895,10 @@
nir->info.has_transform_feedback_varyings) {
NIR_PASS(_, nir, nir_opt_constant_folding);
NIR_PASS(_, nir, nir_io_add_intrinsic_xfb_info);
- NIR_PASS(_, nir, pan_nir_lower_xfb);
+ /* iter17: panvk-specific replacement for pan_nir_lower_xfb that handles
+ * primitive decomposition for non-LIST topologies. Single-store LIST
+ * fast path matches iter13 behavior. */
+ NIR_PASS(_, nir, panvk_per_arch(nir_lower_xfb));
}
#endif
}
diff -urN a/src/panfrost/vulkan/panvk_vX_xfb_lower.c b/src/panfrost/vulkan/panvk_vX_xfb_lower.c
--- a/src/panfrost/vulkan/panvk_vX_xfb_lower.c 1970-01-01 01:00:00.000000000 +0100
+++ b/src/panfrost/vulkan/panvk_vX_xfb_lower.c 2026-05-21 14:04:04.115354242 +0200
@@ -0,0 +1,486 @@
+/*
+ * Copyright © 2026 mfritsche / claude-noether
+ * SPDX-License-Identifier: MIT
+ *
+ * iter17: panvk-specific replacement for pan_nir_lower_xfb that handles
+ * primitive decomposition for transform_feedback on non-LIST topologies
+ * (TRIANGLE_STRIP/FAN, LINE_STRIP, *_WITH_ADJACENCY).
+ *
+ * Approach: emit a topology dispatch at the start of each store_output
+ * lowering. The shader reads vs.xfb_topology sysval at runtime and branches
+ * into per-topology emission logic. For each affected topology, the lowered
+ * code emits guarded conditional stores — one per primitive this vertex
+ * contributes to, computing the output buffer position via primitive index
+ * and slot within the decomposed primitive.
+ *
+ * For LIST topologies (POINT/LINE/TRIANGLE LIST), takes a fast path that
+ * matches iter13's single-store behavior.
+ *
+ * For TRIANGLE_FAN, the central vertex (v=0) contributes to ALL primitives
+ * as slot 2 — handled via a NIR loop bounded by num_vertices.
+ *
+ * See ~/src/panvk-bifrost/iter17/phase{0,1,2}_*.md for full design context.
+ */
+
+#include "panvk_macros.h"
+
+#if PAN_ARCH < 9
+
+#include "panvk_shader.h"
+
+#include "compiler/nir/nir_builder.h"
+#include "pan_nir.h"
+
+#include <vulkan/vulkan_core.h>
+
+/* ----- Address arithmetic ----- */
+
+static nir_def *
+xfb_store_addr(nir_builder *b, nir_def *buf, nir_def *out_idx,
+ uint16_t stride, uint16_t offset_bytes)
+{
+ nir_def *byte_off = nir_iadd_imm(b,
+ nir_imul_imm(b, out_idx, stride), offset_bytes);
+ return nir_iadd(b, buf, nir_u2u64(b, byte_off));
+}
+
+static void
+emit_list_store(nir_builder *b, nir_def *buf, nir_def *output_count,
+ nir_def *instance_id, nir_def *raw_vid, nir_def *value,
+ uint16_t stride, uint16_t offset_bytes)
+{
+ nir_def *out_idx = nir_iadd(b,
+ nir_imul(b, instance_id, output_count), raw_vid);
+ nir_def *addr = xfb_store_addr(b, buf, out_idx, stride, offset_bytes);
+ nir_store_global(b, value, addr);
+}
+
+static void
+emit_prim_store(nir_builder *b, nir_def *buf, nir_def *output_count,
+ nir_def *instance_id, nir_def *eligible,
+ nir_def *prim_idx, nir_def *slot,
+ uint32_t verts_per_prim,
+ nir_def *value, uint16_t stride, uint16_t offset_bytes)
+{
+ nir_push_if(b, eligible);
+ {
+ nir_def *out_idx = nir_iadd(b,
+ nir_imul(b, instance_id, output_count),
+ nir_iadd(b, nir_imul_imm(b, prim_idx, verts_per_prim), slot));
+ nir_def *addr = xfb_store_addr(b, buf, out_idx, stride, offset_bytes);
+ nir_store_global(b, value, addr);
+ }
+ nir_pop_if(b, NULL);
+}
+
+/* ----- Per-topology emission ----- */
+
+/* TRIANGLE_STRIP: vertex v contributes to prims v, v-1, v-2 (per eligibility). */
+static void
+emit_tri_strip(nir_builder *b, nir_def *v, nir_def *N,
+ nir_def *buf, nir_def *output_count, nir_def *instance_id,
+ nir_def *value, uint16_t stride, uint16_t offset_bytes)
+{
+ nir_def *Nm2 = nir_iadd_imm(b, N, -2);
+ nir_def *Nm1 = nir_iadd_imm(b, N, -1);
+
+ /* Prim v, slot 0: v < N-2 */
+ emit_prim_store(b, buf, output_count, instance_id,
+ nir_ult(b, v, Nm2),
+ v, nir_imm_int(b, 0), 3, value, stride, offset_bytes);
+
+ /* Prim v-1, slot = 1 if prim even else 2: 1 <= v < N-1 */
+ {
+ nir_def *prim = nir_iadd_imm(b, v, -1);
+ nir_def *parity = nir_iand_imm(b, prim, 1u);
+ nir_def *slot = nir_iadd_imm(b, parity, 1);
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 1)),
+ nir_ult(b, v, Nm1));
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, slot, 3, value, stride, offset_bytes);
+ }
+
+ /* Prim v-2, slot = 2 if prim even else 1: 2 <= v < N */
+ {
+ nir_def *prim = nir_iadd_imm(b, v, -2);
+ nir_def *parity = nir_iand_imm(b, prim, 1u);
+ nir_def *slot = nir_isub(b, nir_imm_int(b, 2), parity);
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 2)),
+ nir_ult(b, v, N));
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, slot, 3, value, stride, offset_bytes);
+ }
+}
+
+/* LINE_STRIP: vertex v contributes to prim v slot 0 + prim v-1 slot 1. */
+static void
+emit_line_strip(nir_builder *b, nir_def *v, nir_def *N,
+ nir_def *buf, nir_def *output_count, nir_def *instance_id,
+ nir_def *value, uint16_t stride, uint16_t offset_bytes)
+{
+ nir_def *Nm1 = nir_iadd_imm(b, N, -1);
+
+ /* Prim v, slot 0: v < N-1 */
+ emit_prim_store(b, buf, output_count, instance_id,
+ nir_ult(b, v, Nm1),
+ v, nir_imm_int(b, 0), 2, value, stride, offset_bytes);
+
+ /* Prim v-1, slot 1: 1 <= v < N */
+ {
+ nir_def *prim = nir_iadd_imm(b, v, -1);
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 1)),
+ nir_ult(b, v, N));
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, nir_imm_int(b, 1), 2, value, stride, offset_bytes);
+ }
+}
+
+/* TRIANGLE_FAN: prim p emits {p+1, p+2, 0}.
+ * vertex v=0: contributes to ALL prims as slot 2 (loop required)
+ * vertex v>=1: contributes to prim v-1 as slot 0 (if 1 <= v <= N-2)
+ * vertex v>=2: contributes to prim v-2 as slot 1 (if 2 <= v <= N-1)
+ */
+static void
+emit_tri_fan(nir_builder *b, nir_def *v, nir_def *N,
+ nir_def *buf, nir_def *output_count, nir_def *instance_id,
+ nir_def *value, uint16_t stride, uint16_t offset_bytes)
+{
+ nir_def *Nm1 = nir_iadd_imm(b, N, -1);
+ nir_def *Nm2 = nir_iadd_imm(b, N, -2);
+
+ /* Prim v-1, slot 0: 1 <= v < N-1 */
+ {
+ nir_def *prim = nir_iadd_imm(b, v, -1);
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 1)),
+ nir_ult(b, v, Nm1));
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, nir_imm_int(b, 0), 3, value, stride, offset_bytes);
+ }
+
+ /* Prim v-2, slot 1: 2 <= v < N */
+ {
+ nir_def *prim = nir_iadd_imm(b, v, -2);
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 2)),
+ nir_ult(b, v, N));
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, nir_imm_int(b, 1), 3, value, stride, offset_bytes);
+ }
+
+ /* Central vertex (v == 0): loop over all prims, write to slot 2. */
+ nir_push_if(b, nir_ieq_imm(b, v, 0));
+ {
+ nir_variable *p_var = nir_local_variable_create(b->impl,
+ glsl_uint_type(), "fan_p");
+ nir_store_var(b, p_var, nir_imm_int(b, 0), 0x1);
+ nir_push_loop(b);
+ {
+ nir_def *p = nir_load_var(b, p_var);
+ nir_push_if(b, nir_uge(b, p, Nm2));
+ {
+ nir_jump(b, nir_jump_break);
+ }
+ nir_pop_if(b, NULL);
+
+ nir_def *out_idx = nir_iadd(b,
+ nir_imul(b, instance_id, output_count),
+ nir_iadd_imm(b, nir_imul_imm(b, p, 3), 2));
+ nir_def *addr = xfb_store_addr(b, buf, out_idx, stride, offset_bytes);
+ nir_store_global(b, value, addr);
+
+ nir_store_var(b, p_var, nir_iadd_imm(b, p, 1), 0x1);
+ }
+ nir_pop_loop(b, NULL);
+ }
+ nir_pop_if(b, NULL);
+}
+
+/* LINE_LIST_WITH_ADJACENCY: 4-vertex groups [4i..4i+3]; output {4i+1, 4i+2}.
+ * v contributes if v%4 == 1: prim v/4 slot 0
+ * v contributes if v%4 == 2: prim v/4 slot 1
+ */
+static void
+emit_line_list_adj(nir_builder *b, nir_def *v, nir_def *N,
+ nir_def *buf, nir_def *output_count, nir_def *instance_id,
+ nir_def *value, uint16_t stride, uint16_t offset_bytes)
+{
+ (void)N; /* eligibility is mod-based, not range-based */
+ nir_def *vmod4 = nir_iand_imm(b, v, 3u);
+ nir_def *prim = nir_ushr_imm(b, v, 2); /* v / 4 */
+
+ emit_prim_store(b, buf, output_count, instance_id,
+ nir_ieq_imm(b, vmod4, 1),
+ prim, nir_imm_int(b, 0), 2, value, stride, offset_bytes);
+
+ emit_prim_store(b, buf, output_count, instance_id,
+ nir_ieq_imm(b, vmod4, 2),
+ prim, nir_imm_int(b, 1), 2, value, stride, offset_bytes);
+}
+
+/* LINE_STRIP_WITH_ADJACENCY: prim p emits {p+1, p+2}.
+ * v contributes to prim v-1 slot 0 (1 <= v <= N-2)
+ * v contributes to prim v-2 slot 1 (2 <= v <= N-1)
+ */
+static void
+emit_line_strip_adj(nir_builder *b, nir_def *v, nir_def *N,
+ nir_def *buf, nir_def *output_count, nir_def *instance_id,
+ nir_def *value, uint16_t stride, uint16_t offset_bytes)
+{
+ nir_def *Nm1 = nir_iadd_imm(b, N, -1);
+ nir_def *Nm2 = nir_iadd_imm(b, N, -2);
+
+ /* Prim v-1, slot 0: 1 <= v <= N-2 ⇔ v >= 1 AND v <= N-2 ⇔ v >= 1 AND v < N-1 */
+ {
+ nir_def *prim = nir_iadd_imm(b, v, -1);
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 1)),
+ nir_ult(b, v, Nm1));
+ (void)Nm2;
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, nir_imm_int(b, 0), 2, value, stride, offset_bytes);
+ }
+
+ /* Prim v-2, slot 1: 2 <= v <= N-1 ⇔ v >= 2 AND v < N */
+ {
+ nir_def *prim = nir_iadd_imm(b, v, -2);
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 2)),
+ nir_ult(b, v, N));
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, nir_imm_int(b, 1), 2, value, stride, offset_bytes);
+ }
+}
+
+/* TRIANGLE_LIST_WITH_ADJACENCY: 6-vertex groups; output {6i, 6i+2, 6i+4}.
+ * v contributes if v%6 == 0: prim v/6 slot 0
+ * v contributes if v%6 == 2: prim v/6 slot 1
+ * v contributes if v%6 == 4: prim v/6 slot 2
+ */
+static void
+emit_tri_list_adj(nir_builder *b, nir_def *v, nir_def *N,
+ nir_def *buf, nir_def *output_count, nir_def *instance_id,
+ nir_def *value, uint16_t stride, uint16_t offset_bytes)
+{
+ (void)N;
+ nir_def *vmod6 = nir_umod_imm(b, v, 6);
+ nir_def *prim = nir_udiv_imm(b, v, 6);
+
+ for (uint32_t slot = 0; slot < 3; slot++) {
+ emit_prim_store(b, buf, output_count, instance_id,
+ nir_ieq_imm(b, vmod6, slot * 2),
+ prim, nir_imm_int(b, slot), 3, value, stride, offset_bytes);
+ }
+}
+
+/* TRIANGLE_STRIP_WITH_ADJACENCY: prim i emits:
+ * even i: {2i, 2i+2, 2i+4} (slots 0, 1, 2 ← input indices 2i, 2i+2, 2i+4)
+ * odd i: {2i, 2i+4, 2i+2} (slots 0, 1, 2 ← input indices 2i, 2i+4, 2i+2)
+ *
+ * Only EVEN input vertices contribute (since all output indices are 2*something).
+ * For even input v:
+ * prim v/2 slot 0 (always, if v/2 < N/2-2)
+ * prim (v-2)/2 slot 1 if (v-2)/2 even, slot 2 if odd (when v >= 2)
+ * prim (v-4)/2 slot 2 if (v-4)/2 even, slot 1 if odd (when v >= 4)
+ */
+static void
+emit_tri_strip_adj(nir_builder *b, nir_def *v, nir_def *N,
+ nir_def *buf, nir_def *output_count, nir_def *instance_id,
+ nir_def *value, uint16_t stride, uint16_t offset_bytes)
+{
+ /* Bail for odd input vertices — they never contribute. */
+ nir_def *v_is_even = nir_ieq_imm(b, nir_iand_imm(b, v, 1u), 0);
+ nir_push_if(b, v_is_even);
+ {
+ nir_def *N_half = nir_ushr_imm(b, N, 1);
+ nir_def *max_prim = nir_iadd_imm(b, N_half, -2); /* N/2 - 2 */
+ nir_def *v_half = nir_ushr_imm(b, v, 1);
+
+ /* Prim v/2 slot 0: v/2 < N/2 - 2 */
+ emit_prim_store(b, buf, output_count, instance_id,
+ nir_ult(b, v_half, max_prim),
+ v_half, nir_imm_int(b, 0), 3, value, stride, offset_bytes);
+
+ /* Prim (v-2)/2 = v/2 - 1: v >= 2 AND prim < N/2-2 */
+ {
+ nir_def *prim = nir_iadd_imm(b, v_half, -1);
+ nir_def *parity = nir_iand_imm(b, prim, 1u);
+ nir_def *slot = nir_iadd_imm(b, parity, 1); /* even→1, odd→2 */
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 2)),
+ nir_ult(b, prim, max_prim));
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, slot, 3, value, stride, offset_bytes);
+ }
+
+ /* Prim (v-4)/2 = v/2 - 2: v >= 4 AND prim < N/2-2 */
+ {
+ nir_def *prim = nir_iadd_imm(b, v_half, -2);
+ nir_def *parity = nir_iand_imm(b, prim, 1u);
+ nir_def *slot = nir_isub(b, nir_imm_int(b, 2), parity); /* even→2, odd→1 */
+ nir_def *eligible = nir_iand(b,
+ nir_uge(b, v, nir_imm_int(b, 4)),
+ nir_ult(b, prim, max_prim));
+ emit_prim_store(b, buf, output_count, instance_id, eligible,
+ prim, slot, 3, value, stride, offset_bytes);
+ }
+ }
+ nir_pop_if(b, NULL);
+}
+
+/* ----- Main lowering: per store_output XFB channel ----- */
+
+static void
+lower_xfb_output_iter17(nir_builder *b, nir_intrinsic_instr *intr,
+ unsigned channel_idx, unsigned num_components,
+ unsigned buffer, unsigned offset_words)
+{
+ assert(buffer < MAX_XFB_BUFFERS);
+ assert(nir_intrinsic_component(intr) == 0);
+
+ uint16_t stride = b->shader->info.xfb_stride[buffer] * 4;
+ assert(stride != 0);
+ uint16_t offset_bytes = offset_words * 4;
+
+ BITSET_SET(b->shader->info.system_values_read, SYSTEM_VALUE_VERTEX_ID_ZERO_BASE);
+ BITSET_SET(b->shader->info.system_values_read, SYSTEM_VALUE_INSTANCE_ID);
+
+ nir_def *topology = load_sysval(b, graphics, 32, vs.xfb_topology);
+ nir_def *out_count = load_sysval(b, graphics, 32, vs.xfb_output_count);
+ nir_def *N = nir_load_num_vertices(b);
+ nir_def *v = nir_load_raw_vertex_id_pan(b);
+ nir_def *instance = nir_load_instance_id(b);
+ nir_def *buf = nir_load_xfb_address(b, 64, .base = buffer);
+
+ nir_def *src = intr->src[0].ssa;
+ nir_component_mask_t mask = nir_component_mask(num_components);
+ nir_def *value = nir_channels(b, src, mask << channel_idx);
+
+ /* Topology dispatch ladder. LIST first (fast path). */
+ nir_push_if(b, nir_ieq_imm(b, topology, PANVK_XFB_TOPO_LIST));
+ {
+ emit_list_store(b, buf, out_count, instance, v, value,
+ stride, offset_bytes);
+ }
+ nir_push_else(b, NULL);
+ {
+ /* iter17 Janet Finding 3: gate all non-LIST emission on
+ * output_count > 0. For degenerate input counts (N < min required
+ * for the topology), output_count is 0 and we must emit NO stores
+ * — otherwise N-2 / N-3 / etc. arithmetic underflows in the
+ * eligibility predicates and we falsely fire stores. */
+ nir_push_if(b, nir_ult(b, nir_imm_int(b, 0), out_count));
+ {
+ nir_push_if(b, nir_ieq_imm(b, topology, PANVK_XFB_TOPO_TRI_STRIP));
+ {
+ emit_tri_strip(b, v, N, buf, out_count, instance, value,
+ stride, offset_bytes);
+ }
+ nir_push_else(b, NULL);
+ {
+ nir_push_if(b, nir_ieq_imm(b, topology, PANVK_XFB_TOPO_LINE_STRIP));
+ {
+ emit_line_strip(b, v, N, buf, out_count, instance, value,
+ stride, offset_bytes);
+ }
+ nir_push_else(b, NULL);
+ {
+ nir_push_if(b, nir_ieq_imm(b, topology, PANVK_XFB_TOPO_TRI_FAN));
+ {
+ emit_tri_fan(b, v, N, buf, out_count, instance, value,
+ stride, offset_bytes);
+ }
+ nir_push_else(b, NULL);
+ {
+ nir_push_if(b, nir_ieq_imm(b, topology, PANVK_XFB_TOPO_LINE_LIST_ADJ));
+ {
+ emit_line_list_adj(b, v, N, buf, out_count, instance, value,
+ stride, offset_bytes);
+ }
+ nir_push_else(b, NULL);
+ {
+ nir_push_if(b, nir_ieq_imm(b, topology, PANVK_XFB_TOPO_LINE_STRIP_ADJ));
+ {
+ emit_line_strip_adj(b, v, N, buf, out_count, instance, value,
+ stride, offset_bytes);
+ }
+ nir_push_else(b, NULL);
+ {
+ nir_push_if(b, nir_ieq_imm(b, topology, PANVK_XFB_TOPO_TRI_LIST_ADJ));
+ {
+ emit_tri_list_adj(b, v, N, buf, out_count, instance, value,
+ stride, offset_bytes);
+ }
+ nir_push_else(b, NULL);
+ {
+ /* TRI_STRIP_ADJ — last case */
+ emit_tri_strip_adj(b, v, N, buf, out_count, instance, value,
+ stride, offset_bytes);
+ }
+ nir_pop_if(b, NULL);
+ }
+ nir_pop_if(b, NULL);
+ }
+ nir_pop_if(b, NULL);
+ }
+ nir_pop_if(b, NULL);
+ }
+ nir_pop_if(b, NULL);
+ }
+ nir_pop_if(b, NULL);
+ }
+ nir_pop_if(b, NULL); /* Janet Finding 3: close output_count > 0 guard */
+ }
+ nir_pop_if(b, NULL);
+}
+
+/* Mirror of pan_nir_lower_xfb's lower_xfb: load_vertex_id rewrite +
+ * dispatch store_output through our topology-aware emission. */
+static bool
+lower_xfb_iter17(nir_builder *b, nir_intrinsic_instr *intr,
+ UNUSED void *data)
+{
+ if (intr->intrinsic == nir_intrinsic_load_vertex_id) {
+ b->cursor = nir_instr_remove(&intr->instr);
+ nir_def *repl = nir_iadd(b, nir_load_raw_vertex_id_pan(b),
+ nir_load_raw_vertex_offset_pan(b));
+ nir_def_rewrite_uses(&intr->def, repl);
+ return true;
+ }
+
+ if (intr->intrinsic != nir_intrinsic_store_output)
+ return false;
+
+ bool progress = false;
+ b->cursor = nir_before_instr(&intr->instr);
+
+ /* io_xfb has only out[0,1]; the other 2 channels are in io_xfb2.
+ * Outer loop selects which annotation; inner picks which channel. */
+ for (unsigned i = 0; i < 2; ++i) {
+ nir_io_xfb xfb = i ? nir_intrinsic_io_xfb2(intr)
+ : nir_intrinsic_io_xfb(intr);
+ for (unsigned j = 0; j < 2; ++j) {
+ if (!xfb.out[j].num_components)
+ continue;
+ lower_xfb_output_iter17(b, intr, i * 2 + j, xfb.out[j].num_components,
+ xfb.out[j].buffer, xfb.out[j].offset);
+ progress = true;
+ }
+ }
+
+ if (progress)
+ nir_instr_remove(&intr->instr);
+ return progress;
+}
+
+bool
+panvk_per_arch(nir_lower_xfb)(nir_shader *nir)
+{
+ return nir_shader_intrinsics_pass(
+ nir, lower_xfb_iter17, nir_metadata_control_flow, NULL);
+}
+
+#endif /* PAN_ARCH < 9 */