[PATCH] drm/amd/display: add debug logs for dm_crtc_helper_atomic_check

[Simon Ser]

Instead of silently failing the atomic check, explain what happened via
a debug log. This makes it easier for user-space to figure out why
something failed.

Signed-off-by: Simon Ser <contact at emersion.fr>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Harry Wentland <hwentlan at amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 862a59703060..313501cc39fc 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6068,8 +6068,10 @@ static int dm_crtc_helper_atomic_check(struct drm_crtc *crtc,
 	 * userspace which stops using the HW cursor altogether in response to the resulting EINVAL.
 	 */
 	if (crtc_state->enable &&
-	    !(crtc_state->plane_mask & drm_plane_mask(crtc->primary)))
+	    !(crtc_state->plane_mask & drm_plane_mask(crtc->primary))) {
+		DRM_DEBUG_ATOMIC("Can't enable a CRTC without enabling the primary plane\n");
 		return -EINVAL;
+	}
 
 	/* In some use cases, like reset, no stream is attached */
 	if (!dm_crtc_state->stream)
@@ -6078,6 +6080,7 @@ static int dm_crtc_helper_atomic_check(struct drm_crtc *crtc,
 	if (dc_validate_stream(dc, dm_crtc_state->stream) == DC_OK)
 		return 0;
 
+	DRM_DEBUG_ATOMIC("Failed DC stream validation\n");
 	return ret;
 }
 
-- 
2.29.2