[Mesa-dev] [PATCH 7/7] radeonsi: always use PFP_SYNC_ME when doing flushes and waits

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

This is typically used by the closed driver before SURFACE_SYNC.
---
 src/gallium/drivers/radeonsi/si_state_draw.c | 10 +++++++++-
 src/gallium/drivers/radeonsi/sid.h           |  1 +
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/radeonsi/si_state_draw.c b/src/gallium/drivers/radeonsi/si_state_draw.c
index 3efaecc..d31f77f 100644
--- a/src/gallium/drivers/radeonsi/si_state_draw.c
+++ b/src/gallium/drivers/radeonsi/si_state_draw.c
@@ -706,8 +706,16 @@ void si_emit_cache_flush(struct si_context *si_ctx, struct r600_atom *atom)
 		radeon_emit(cs, EVENT_TYPE(V_028A90_VGT_STREAMOUT_SYNC) | EVENT_INDEX(0));
 	}
 
+	/* Make sure ME is idle (it executes most packets) before continuing.
+	 * This prevents read-after-write hazards between PFP and ME.
+	 */
+	if (cp_coher_cntl || (sctx->flags & SI_CONTEXT_CS_PARTIAL_FLUSH)) {
+		radeon_emit(cs, PKT3(PKT3_PFP_SYNC_ME, 0, 0));
+		radeon_emit(cs, 0);
+	}
+
 	/* When one of the DEST_BASE flags is set, SURFACE_SYNC waits for idle.
-	 * Therefore, it should be last.
+	 * Therefore, it should be last. Done in PFP.
 	 */
 	if (cp_coher_cntl) {
 		/* ACQUIRE_MEM is only required on a compute ring. */
diff --git a/src/gallium/drivers/radeonsi/sid.h b/src/gallium/drivers/radeonsi/sid.h
index f0aa605..11d6090 100644
--- a/src/gallium/drivers/radeonsi/sid.h
+++ b/src/gallium/drivers/radeonsi/sid.h
@@ -132,6 +132,7 @@
 #define		COPY_DATA_DST_SEL(x)		(((x) & 0xf) << 8)
 #define		COPY_DATA_COUNT_SEL		(1 << 16)
 #define		COPY_DATA_WR_CONFIRM		(1 << 20)
+#define PKT3_PFP_SYNC_ME		       0x42 /* r7xx+ */
 #define PKT3_SURFACE_SYNC                      0x43 /* deprecated on CIK, use ACQUIRE_MEM */
 #define PKT3_ME_INITIALIZE                     0x44 /* not on CIK */
 #define PKT3_COND_WRITE                        0x45
-- 
2.5.0