anv: Emit a dummy MEDIA_VFE_STATE before switching from GPGPU to 3D

There is an object-level  preemption workaround which requires this.
However, even without object-level preemption, we seem to have issues
with geometry flickering when 3D and compute are combined in the same
batch and this appears to fix it.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109630
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111267
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/intel/vulkan/genX_cmd_buffer.c b/src/intel/vulkan/genX_cmd_buffer.c
index 5b76ac6167935d2ac943c257fab3b5a9f0a22815..a91cffd8fc7ae54892d574c555a238b7ce3fd1a6 100644 (file)
--- a/src/intel/vulkan/genX_cmd_buffer.c
+++ b/src/intel/vulkan/genX_cmd_buffer.c
@@ -3827,6 +3827,25 @@ genX(flush_pipeline_select)(struct anv_cmd_buffer *cmd_buffer,
       anv_batch_emit(&cmd_buffer->batch, GENX(3DSTATE_CC_STATE_POINTERS), t);
 #endif
 
+#if GEN_GEN == 9
+   if (pipeline == _3D) {
+      /* There is a mid-object preemption workaround which requires you to
+       * re-emit MEDIA_VFE_STATE after switching from GPGPU to 3D.  However,
+       * even without preemption, we have issues with geometry flickering when
+       * GPGPU and 3D are back-to-back and this seems to fix it.  We don't
+       * really know why.
+       */
+      const uint32_t subslices =
+         MAX2(cmd_buffer->device->instance->physicalDevice.subslice_total, 1);
+      anv_batch_emit(&cmd_buffer->batch, GENX(MEDIA_VFE_STATE), vfe) {
+         vfe.MaximumNumberofThreads =
+            devinfo->max_cs_threads * subslices - 1;
+         vfe.NumberofURBEntries     = 2;
+         vfe.URBEntryAllocationSize = 2;
+      }
+   }
+#endif
+
    /* From "BXML » GT » MI » vol1a GPU Overview » [Instruction]
     * PIPELINE_SELECT [DevBWR+]":
     *