[Mesa-dev] [PATCH] radv: only sync CP DMA for transfer operations or bottom pipe

[Samuel Pitoiset]

CP DMA can only be busy when the driver copies buffers. The
only affected Vulkan commands are vkCmdCopyBuffer() and
vkCmdUpdateBuffer() (because we fallback to a copy depending on
a threshold). Clear operations are currently not concerned
because the driver always syncs after the last DMA operation.

Per the spec, these two operations have to be externally
synchronized with VK_PIPELINE_STAGE_TRANSFER_BIT.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/amd/vulkan/radv_cmd_buffer.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/amd/vulkan/radv_cmd_buffer.c b/src/amd/vulkan/radv_cmd_buffer.c
index 1859c9c960..7367e24fd2 100644
--- a/src/amd/vulkan/radv_cmd_buffer.c
+++ b/src/amd/vulkan/radv_cmd_buffer.c
@@ -4519,7 +4519,9 @@ radv_barrier(struct radv_cmd_buffer *cmd_buffer,
 	/* Make sure CP DMA is idle because the driver might have performed a
 	 * DMA operation for copying or filling buffers/images.
 	 */
-	si_cp_dma_wait_for_idle(cmd_buffer);
+	if (info->srcStageMask & (VK_PIPELINE_STAGE_TRANSFER_BIT |
+				  VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT))
+		si_cp_dma_wait_for_idle(cmd_buffer);
 
 	cmd_buffer->state.flush_bits |= dst_flush_bits;
 }
@@ -4576,7 +4578,9 @@ static void write_event(struct radv_cmd_buffer *cmd_buffer,
 	/* Make sure CP DMA is idle because the driver might have performed a
 	 * DMA operation for copying or filling buffers/images.
 	 */
-	si_cp_dma_wait_for_idle(cmd_buffer);
+	if (stageMask & (VK_PIPELINE_STAGE_TRANSFER_BIT |
+			 VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT))
+		si_cp_dma_wait_for_idle(cmd_buffer);
 
 	/* TODO: Emit EOS events for syncing PS/CS stages. */
 
-- 
2.19.1