drm/amd/display: Fixed read/write pointer issue for get dmub trace

[Why]
Driver get wrap around dmub trace data due to read pointer being
increased incorrectly when there are multiple interrupt
queues with very short interval

[How]
Check read/write pointer before copying data from ring buffer

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 2 insertions, 6 deletions

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 b9d8cfef0a1a..68453c29c617 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
+++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
@@ -172,14 +172,10 @@ bool dc_dmub_srv_notify_stream_mask(struct dc_dmub_srv *dc_dmub_srv,
 		       stream_mask, timeout) == DMUB_STATUS_OK;
 }
 
-enum dmub_status dc_dmub_srv_get_dmub_outbox0_msg(const struct dc *dc, struct dmcub_trace_buf_entry *entry)
+bool dc_dmub_srv_get_dmub_outbox0_msg(const struct dc *dc, struct dmcub_trace_buf_entry *entry)
 {
 	struct dmub_srv *dmub = dc->ctx->dmub_srv->dmub;
-	enum dmub_status status;
-
-	status = dmub_srv_get_outbox0_msg(dmub, entry);
-
-	return status;
+	return dmub_srv_get_outbox0_msg(dmub, entry);
 }
 
 void dc_dmub_trace_event_control(struct dc *dc, bool enable)