[Why]
The call to drm_crtc_vblank_get can fail if vblank is disabled and
we try to increment the reference.
Since drm_crtc_vblank_get internally drops the reference when it fails
it means the subsequent drm_crtc_vblank_put(...) when closing the file
drops a zero reference.
This was found via igt@kms_plane@pixel-format-pipe-A-planes.
[How]
Check the return code and return it on failure.
We wouldn't have been able to enable CRC reading anyway since vblank
wasn't enabled.
Cc: David Francis <David.Francis@xxxxxxx>
Cc: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx>
Cc: Leo Li <sunpeng.li@xxxxxxx>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
index b01256a4692e..f675626ef56b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
@@ -105,6 +105,7 @@ int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name)
struct drm_dp_aux *aux = NULL;
bool enable = false;
bool enabled = false;
+ int ret;
enum amdgpu_dm_pipe_crc_source source = dm_parse_crc_source(src_name);
@@ -175,7 +176,10 @@ int amdgpu_dm_crtc_set_crc_source(struct drm_crtc *crtc, const char *src_name)
*/
enabled = amdgpu_dm_is_valid_crc_source(crtc_state->crc_src);
if (!enabled && enable) {
- drm_crtc_vblank_get(crtc);
+ ret = drm_crtc_vblank_get(crtc);
+ if (ret)
+ return ret;
+
if (dm_is_crc_source_dprx(source)) {
if (drm_dp_start_crc(aux, crtc)) {
DRM_DEBUG_DRIVER("dp start crc failed\n");
--
2.17.1
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