drm/amd/display: Retry AUX write when fail occurs

[ Upstream commit ef67d792a2fc578319399f605fbec2f99ecc06ea ]

[Why]
In dm_dp_aux_transfer() now, we forget to handle AUX_WR fail cases. We
suppose every write wil get done successfully and hence some AUX
commands might not sent out indeed.

[How]
Check if AUX_WR success. If not, retry it.

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index e5ecc5affa1eb7c46eb2005afa09d2c7b1aca548..5098fc98cc2552cf498d67ff8842762f94f38396 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -67,7 +67,7 @@ static ssize_t dm_dp_aux_transfer(struct drm_dp_aux *aux,
        result = dc_link_aux_transfer_raw(TO_DM_AUX(aux)->ddc_service, &payload,
                                      &operation_result);
 
-       if (payload.write)
+       if (payload.write && result >= 0)
                result = msg->size;
 
        if (result < 0)