On Fri, Mar 17, 2017 at 11:18:06PM +0200, ville.syrjala@xxxxxxxxxxxxxxx wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > We currently hold a vblank referenced while trying to evade the > vblank, but we drop it as soon as we've done that. After all the > planes have been committed we are quite likely to grab a new vblank > reference for delivering the flip event. This causes the vblank > interrupt to do a enable->enable->disable ping-pong during many > commits. If we instead hang on to the original vblank reference > across the entire commit we can eliminate that ping-pong. Does it make sense to take an an extra vblank_get() only if we have an event to deliver? > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_sprite.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c > index 26c8bdcd7e72..337e884252e5 100644 > --- a/drivers/gpu/drm/i915/intel_sprite.c > +++ b/drivers/gpu/drm/i915/intel_sprite.c > @@ -137,8 +137,6 @@ void intel_pipe_update_start(struct intel_crtc *crtc) > > finish_wait(wq, &wait); > if (crtc->base.state->event) drm_crtc_vblank_get(&crtc->base); drm_crtc_vblank_put(&crtc->base); > crtc->debug.scanline_start = scanline; > crtc->debug.start_vbl_time = ktime_get(); > crtc->debug.start_vbl_count = intel_crtc_get_vblank_counter(crtc); > @@ -185,6 +183,15 @@ void intel_pipe_update_end(struct intel_crtc *crtc, struct intel_flip_work *work > crtc->base.state->event = NULL; > > + /* > + * The reference was taken in intel_pipe_update_start(). It could > + * have been dropped as soon as the vblank was evaded, but we hold > + * on to it until this time to avoid the extra vblank interrupt > + * enable->disable->enable ping-pong whenever we have to deliver > + * an event. > + */ > + drm_crtc_vblank_put(&crtc->base); } > local_irq_enable(); -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
