[PATCH 5.4 134/434] drm/amd/display: wait for set pipe mcp command completion

[Greg Kroah-Hartman]

From: Josip Pavic <Josip.Pavic@xxxxxxx>

[ Upstream commit 15caeabc5787c15babad7ee444afe9c26df1c8b3 ]

[Why]
When the driver sends a pipe set command to the DMCU FW, it does not wait
for the command to complete. This can lead to unpredictable behavior if,
for example, the driver were to request a pipe disable to the FW via MCP,
then power down some hardware before the firmware has completed processing
the command.

[How]
Wait for the DMCU FW to finish processing set pipe commands

Signed-off-by: Josip Pavic <Josip.Pavic@xxxxxxx>
Reviewed-by: Anthony Koo <Anthony.Koo@xxxxxxx>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/amd/display/dc/dce/dce_abm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
index 58bd131d5b48..7700a855d77c 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c
@@ -77,6 +77,9 @@ static bool dce_abm_set_pipe(struct abm *abm, uint32_t controller_id)
 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);
 
+	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0,
+			1, 80000);
+
 	return true;
 }
 
-- 
2.20.1