drm/vblank: Switch drm_driver->get_vblank_timestamp to return a bool

There's really no reason for anything more:
- Calling this while the crtc vblank stuff isn't set up is a driver
  bug. Those places alrready DRM_ERROR.
- Calling this when the crtc is off is either a driver bug (calling
  drm_crtc_handle_vblank at the wrong time) or a core bug (for
  anything else). Again, we DRM_ERROR.
- EINVAL is checked at higher levels already, and if we'd use struct
  drm_crtc * instead of (dev, pipe) it would be real obvious that
  those are again core bugs.

The only valid failure mode is crap hardware that couldn't sample a
useful timestamp, to ask the core to just grab a not-so-accurate
timestamp. Bool is perfectly fine for that.

v2: Also fix up the one caller, I lost that in the shuffling (Jani).

v3: Fixup commit message (Neil).

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Cc: Eric Anholt <eric@anholt.net>
Cc: Rob Clark <robdclark@gmail.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170509140329.24114-1-daniel.vetter@ffwll.ch

1 files changed, 7 insertions, 7 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 832be632478f..a1b97809305e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -945,19 +945,19 @@ void amdgpu_disable_vblank_kms(struct drm_device *dev, unsigned int pipe)
  *
  * Gets the timestamp on the requested crtc based on the
  * scanout position.  (all asics).
- * Returns postive status flags on success, negative error on failure.
+ * Returns true on success, false on failure.
  */
-int amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
-				    int *max_error,
-				    struct timeval *vblank_time,
-				    unsigned flags)
+bool amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
+				     int *max_error,
+				     struct timeval *vblank_time,
+				     unsigned flags)
 {
 	struct drm_crtc *crtc;
 	struct amdgpu_device *adev = dev->dev_private;
 
 	if (pipe >= dev->num_crtcs) {
 		DRM_ERROR("Invalid crtc %u\n", pipe);
-		return -EINVAL;
+		return false;
 	}
 
 	/* Get associated drm_crtc: */
@@ -966,7 +966,7 @@ int amdgpu_get_vblank_timestamp_kms(struct drm_device *dev, unsigned int pipe,
 		/* This can occur on driver load if some component fails to
 		 * initialize completely and driver is unloaded */
 		DRM_ERROR("Uninitialized crtc %d\n", pipe);
-		return -EINVAL;
+		return false;
 	}
 
 	/* Helper routine in DRM core does all the work: */