Commit 3c184f69 authored by Ville Syrjälä's avatar Ville Syrjälä
Browse files

drm: Change {pixel,line,frame}dur_ns from s64 to int 



Using s64 for the timestamping constants is wasteful. Signed 32bit
integers get us a range of over +-2 seconds. Presuming that no-one
wants to a vrefresh rate less than 0.5, we can switch to using int
for the timestamping constants. We save a few bytes in drm_crtc and
avoid a bunch of 64bit math.

Reviewed-by: default avatar <mario.kleiner.de@gmail.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
parent 77666b72

drivers/gpu/drm/drm_irq.c

+9 −9
Original line number Diff line number Diff line
@@ -450,7 +450,7 @@ int drm_control(struct drm_device *dev, void *data, 
void drm_calc_timestamping_constants(struct drm_crtc *crtc,

				     const struct drm_display_mode *mode)

{

	s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;

	int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;

	int dotclock = mode->crtc_clock;



	/* Fields of interlaced scanout modes are only half a frame duration.
@@ -483,8 +483,8 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc, 
		  crtc->base.id, mode->crtc_htotal,

		  mode->crtc_vtotal, mode->crtc_vdisplay);

	DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",

		  crtc->base.id, dotclock, (int) framedur_ns,

		  (int) linedur_ns, (int) pixeldur_ns);

		  crtc->base.id, dotclock, framedur_ns,

		  linedur_ns, pixeldur_ns);

}

EXPORT_SYMBOL(drm_calc_timestamping_constants);
@@ -544,7 +544,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 
	struct timeval tv_etime;

	int vbl_status, vtotal, vdisplay;

	int vpos, hpos, i;

	s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;

	int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;

	bool invbl;



	if (crtc < 0 || crtc >= dev->num_crtcs) {
@@ -607,18 +607,18 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 
		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);



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

		if (duration_ns <= (s64) *max_error)

		if (duration_ns <= *max_error)

			break;

	}



	/* Noisy system timing? */

	if (i == DRM_TIMESTAMP_MAXRETRIES) {

		DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",

			  crtc, (int) duration_ns/1000, *max_error/1000, i);

			  crtc, duration_ns/1000, *max_error/1000, i);

	}



	/* Return upper bound of timestamp precision error. */

	*max_error = (int) duration_ns;

	*max_error = duration_ns;



	/* Check if in vblank area:

	 * vpos is >=0 in video scanout area, but negative
@@ -631,7 +631,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 
	 * since start of scanout at first display scanline. delta_ns

	 * can be negative if start of scanout hasn't happened yet.

	 */

	delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns;

	delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;



	/* Is vpos outside nominal vblank area, but less than

	 * 1/100 of a frame height away from start of vblank?
@@ -669,7 +669,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, 
		  crtc, (int)vbl_status, hpos, vpos,

		  (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);

		  duration_ns/1000, i);



	vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;

	if (invbl)

include/drm/drm_crtc.h

+1 −1
Original line number Diff line number Diff line
@@ -447,7 +447,7 @@ struct drm_crtc { 
	uint16_t *gamma_store;



	/* Constants needed for precise vblank and swap timestamping. */

	s64 framedur_ns, linedur_ns, pixeldur_ns;

	int framedur_ns, linedur_ns, pixeldur_ns;



	/* if you are using the helper */

	void *helper_private;

CRA Git | Maintained and supported by SUSTech CRA and CCSE