[PATCH 13/20] drm/amd/display: Switch DMCUB notify idle command to NO_WAIT

[Rodrigo Siqueira]

From: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>

[Why]
Race condition between notification of driver idle and the command being
processed. We could theoretically enter idle between the submission and
the wait for idle that occurs after.

[How]
Switch the notification to NO_WAIT to avoid the RPTR access.

Reviewed-by: Sung joon Kim <sungjoon.kim at amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira at amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
index 7724dcadecba..dadeaa9c92dd 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
+++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
@@ -1209,7 +1209,8 @@ static void dc_dmub_srv_notify_idle(const struct dc *dc, bool allow_idle)
 	}
 
 	/* NOTE: This does not use the "wake" interface since this is part of the wake path. */
-	dm_execute_dmub_cmd(dc->ctx, &cmd, DM_DMUB_WAIT_TYPE_WAIT);
+	/* We also do not perform a wait since DMCUB could enter idle after the notification. */
+	dm_execute_dmub_cmd(dc->ctx, &cmd, DM_DMUB_WAIT_TYPE_NO_WAIT);
 }
 
 static void dc_dmub_srv_exit_low_power_state(const struct dc *dc)
-- 
2.42.0