[Mesa-dev] [PATCH] radv: set WD_SWITCH_ON_EOP=1 when drawing primitives from a stream output buffer

[Samuel Pitoiset]

According to RadeonSI, this seems to be required by the hardware
to avoid GPU hangs. I think I just forgot to set that bit when I
implemented VK_EXT_transform_feedback.

This fixes a GPU hang with Space Engineers and DXVK.

Cc: "19.0" "19.1" <mesa-stable at lists.freedesktop.org>
Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/amd/vulkan/radv_cmd_buffer.c | 1 +
 src/amd/vulkan/radv_private.h    | 1 +
 src/amd/vulkan/si_cmd_buffer.c   | 7 +++++++
 3 files changed, 9 insertions(+)

diff --git a/src/amd/vulkan/radv_cmd_buffer.c b/src/amd/vulkan/radv_cmd_buffer.c
index 963118215fa..b04c998fac2 100644
--- a/src/amd/vulkan/radv_cmd_buffer.c
+++ b/src/amd/vulkan/radv_cmd_buffer.c
@@ -2202,6 +2202,7 @@ radv_emit_draw_registers(struct radv_cmd_buffer *cmd_buffer,
 	ia_multi_vgt_param =
 		si_get_ia_multi_vgt_param(cmd_buffer, draw_info->instance_count > 1,
 					  draw_info->indirect,
+					  !!draw_info->strmout_buffer,
 					  draw_info->indirect ? 0 : draw_info->count);
 
 	if (state->last_ia_multi_vgt_param != ia_multi_vgt_param) {
diff --git a/src/amd/vulkan/radv_private.h b/src/amd/vulkan/radv_private.h
index 352072f8ff3..df85d0cf889 100644
--- a/src/amd/vulkan/radv_private.h
+++ b/src/amd/vulkan/radv_private.h
@@ -1160,6 +1160,7 @@ void si_write_scissors(struct radeon_cmdbuf *cs, int first,
 		       const VkViewport *viewports, bool can_use_guardband);
 uint32_t si_get_ia_multi_vgt_param(struct radv_cmd_buffer *cmd_buffer,
 				   bool instanced_draw, bool indirect_draw,
+				   bool count_from_stream_output,
 				   uint32_t draw_vertex_count);
 void si_cs_emit_write_event_eop(struct radeon_cmdbuf *cs,
 				enum chip_class chip_class,
diff --git a/src/amd/vulkan/si_cmd_buffer.c b/src/amd/vulkan/si_cmd_buffer.c
index e75c6d127d6..e73c13762e5 100644
--- a/src/amd/vulkan/si_cmd_buffer.c
+++ b/src/amd/vulkan/si_cmd_buffer.c
@@ -561,6 +561,7 @@ radv_prims_for_vertices(struct radv_prim_vertex_count *info, unsigned num)
 uint32_t
 si_get_ia_multi_vgt_param(struct radv_cmd_buffer *cmd_buffer,
 			  bool instanced_draw, bool indirect_draw,
+			  bool count_from_stream_output,
 			  uint32_t draw_vertex_count)
 {
 	enum chip_class chip_class = cmd_buffer->device->physical_device->rad_info.chip_class;
@@ -622,6 +623,12 @@ si_get_ia_multi_vgt_param(struct radv_cmd_buffer *cmd_buffer,
 		    (instanced_draw || indirect_draw))
 			partial_vs_wave = true;
 
+		/* Hardware requirement when drawing primitives from a stream
+		 * output buffer.
+		 */
+		if (count_from_stream_output)
+			wd_switch_on_eop = true;
+
 		/* If the WD switch is false, the IA switch must be false too. */
 		assert(wd_switch_on_eop || !ia_switch_on_eop);
 	}
-- 
2.21.0