Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e62f2f5a authored by Imre Deak's avatar Imre Deak Committed by Dave Airlie
Browse files

drm: use monotonic time in drm_calc_vbltimestamp_from_scanoutpos 



For measuring duration we want to avoid that our start/end timestamps
jump, so use monotonic instead of real time for that.

Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Reviewed-by: mario.kleiner
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 11e68685

drivers/gpu/drm/drm_irq.c

+12 −6
Original line number Diff line number Diff line
@@ -576,7 +576,8 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 
					  unsigned flags,

					  struct drm_crtc *refcrtc)

{

	struct timeval stime, raw_time;

	ktime_t stime, etime, mono_time_offset;

	struct timeval tv_etime;

	struct drm_display_mode *mode;

	int vbl_status, vtotal, vdisplay;

	int vpos, hpos, i;
@@ -625,13 +626,14 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 
		preempt_disable();



		/* Get system timestamp before query. */

		do_gettimeofday(&stime);

		stime = ktime_get();



		/* Get vertical and horizontal scanout pos. vpos, hpos. */

		vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos);



		/* Get system timestamp after query. */

		do_gettimeofday(&raw_time);

		etime = ktime_get();

		mono_time_offset = ktime_get_monotonic_offset();



		preempt_enable();
@@ -642,7 +644,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 
			return -EIO;

		}



		duration_ns = timeval_to_ns(&raw_time) - timeval_to_ns(&stime);

		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);



		/* Accept result with <  max_error nsecs timing uncertainty. */

		if (duration_ns <= (s64) *max_error)
@@ -689,14 +691,18 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 
		vbl_status |= 0x8;

	}



	etime = ktime_sub(etime, mono_time_offset);

	/* save this only for debugging purposes */

	tv_etime = ktime_to_timeval(etime);

	/* Subtract time delta from raw timestamp to get final

	 * vblank_time timestamp for end of vblank.

	 */

	*vblank_time = ns_to_timeval(timeval_to_ns(&raw_time) - delta_ns);

	etime = ktime_sub_ns(etime, delta_ns);

	*vblank_time = ktime_to_timeval(etime);



	DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",

		  crtc, (int)vbl_status, hpos, vpos,

		  (long)raw_time.tv_sec, (long)raw_time.tv_usec,

		  (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,

		  (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,

		  (int)duration_ns/1000, i);