From 166c68914b494c45fbd9e4a736a0fe5867581b6a Mon Sep 17 00:00:00 2001
From: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Date: Fri, 13 Mar 2026 10:00:12 -0400
Subject: [PATCH] zink: use EXT_primitive_restart_index

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40784>
---
 src/gallium/drivers/zink/VP_ZINK_requirements.json | 6 +++++-
 src/gallium/drivers/zink/zink_device_info.py       | 3 +++
 src/gallium/drivers/zink/zink_draw.cpp             | 2 ++
 src/gallium/drivers/zink/zink_screen.c             | 2 +-
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/zink/VP_ZINK_requirements.json b/src/gallium/drivers/zink/VP_ZINK_requirements.json
index a3f1c0b7768..5e773b96875 100644
--- a/src/gallium/drivers/zink/VP_ZINK_requirements.json
+++ b/src/gallium/drivers/zink/VP_ZINK_requirements.json
@@ -505,7 +505,8 @@
                 "VK_EXT_primitives_generated_query": 1,
                 "VK_EXT_color_write_enable": 1,
                 "VK_EXT_extended_dynamic_state3": 1,
-                "VK_EXT_descriptor_buffer": 1
+                "VK_EXT_descriptor_buffer": 1,
+                "VK_EXT_primitive_restart_index": 1
             },
             "features": {
                 "VkPhysicalDevicePrimitivesGeneratedQueryFeaturesEXT": {
@@ -525,6 +526,9 @@
                 },
                 "VkPhysicalDeviceDescriptorBufferFeaturesEXT": {
                     "descriptorBuffer": true
+                },
+                "VkPhysicalDevicePrimitiveRestartIndexFeaturesEXT": {
+                    "primitiveRestartIndex": true
                 }
             }
         },
diff --git a/src/gallium/drivers/zink/zink_device_info.py b/src/gallium/drivers/zink/zink_device_info.py
index 00a8dd0608b..e932ad2400f 100644
--- a/src/gallium/drivers/zink/zink_device_info.py
+++ b/src/gallium/drivers/zink/zink_device_info.py
@@ -330,6 +330,9 @@ EXTENSIONS = [
               alias="list_restart",
               features=True,
               conditions=["$feats.primitiveTopologyListRestart"]),
+    Extension("VK_EXT_primitive_restart_index",
+              alias="restart_index",
+              features=True),
     Extension("VK_KHR_dedicated_allocation",
               alias="dedicated"),
     Extension("VK_EXT_descriptor_indexing",
diff --git a/src/gallium/drivers/zink/zink_draw.cpp b/src/gallium/drivers/zink/zink_draw.cpp
index 2bcbba8ce34..28d99da1318 100644
--- a/src/gallium/drivers/zink/zink_draw.cpp
+++ b/src/gallium/drivers/zink/zink_draw.cpp
@@ -778,6 +778,8 @@ zink_draw(struct pipe_context *pctx,
       VKCTX(CmdSetPrimitiveRestartEnable)(bs->cmdbuf, dinfo->primitive_restart);
       ctx->primitive_restart = dinfo->primitive_restart;
    }
+   if (dinfo->primitive_restart && screen->info.have_EXT_primitive_restart_index)
+      VKCTX(CmdSetPrimitiveRestartIndexEXT)(bs->cmdbuf, dinfo->restart_index);
 
    if (zink_program_has_descriptors(&ctx->curr_program->base) && (BATCH_CHANGED || ctx->dd.push_state_changed[0] || ctx->dd.state_changed[0] || pipeline_changed))
       zink_descriptors_update(ctx, ZINK_PIPELINE_GFX);
diff --git a/src/gallium/drivers/zink/zink_screen.c b/src/gallium/drivers/zink/zink_screen.c
index 01518d4e002..e56ecb7a7c0 100644
--- a/src/gallium/drivers/zink/zink_screen.c
+++ b/src/gallium/drivers/zink/zink_screen.c
@@ -731,7 +731,7 @@ zink_init_screen_caps(struct zink_screen *screen)
    caps->texrect = false;
    caps->multi_draw_indirect_partial_stride = false;
    caps->anisotropic_filter = screen->info.feats.features.samplerAnisotropy;
-   caps->emulate_nonfixed_primitive_restart = true;
+   caps->emulate_nonfixed_primitive_restart = !screen->info.have_EXT_primitive_restart_index;
    {
       uint32_t modes = BITFIELD_BIT(MESA_PRIM_LINE_STRIP) |
          BITFIELD_BIT(MESA_PRIM_TRIANGLE_STRIP) |