On Tue, Apr 30, 2019 at 01:44:19PM +0300, Ville Syrjälä wrote: > On Tue, Apr 30, 2019 at 11:37:46AM +0200, Linus Walleij wrote: > > The 50 ms default timeout waiting for vblanks is too small > > for the first vblank from the ST-Ericsson MCDE display > > controller over DSI. Presumably this is because the DSI > > display is command-mode only and the state machine will > > take some time setting up its state for the first display > > update, and we hit a timeout. 100 ms makes it pass without > > problems. > > > > Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > > --- > > After a quite prolonged hunting for the cause of missed > > vblanks in the MCDE driver I finally realized it timed > > out because it was simply taking some time on the first > > vblank. 50 ms makes sense on 60Hz monitors for sure, > > but an embedded DSI state machine can be slow, as it > > turns out. > > > > Tell me if this should be a per-driver variable and I > > will think of something. > > --- > > drivers/gpu/drm/drm_atomic_helper.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > > index 40ac19848034..f0aa7b195d79 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -1424,7 +1424,7 @@ drm_atomic_helper_wait_for_vblanks(struct drm_device *dev, > > ret = wait_event_timeout(dev->vblank[i].queue, > > old_state->crtcs[i].last_vblank_count != > > drm_crtc_vblank_count(crtc), > > - msecs_to_jiffies(50)); > > + msecs_to_jiffies(100)); > > 50ms is pretty tight for 24Hz as well. I suppose we could make this > depend on the expected frame/field duration, but it's generally > indicative of a programming error of some sort, so as long as it's > long enough I think we're good. > > Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Yeah makes sense to bump this a bit. An uber-fancy version would look at the programmed refresh rate and maybe give the driver extra slack for the first frame after a modeset. But this is good enough. Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > > > > > WARN(!ret, "[CRTC:%d:%s] vblank wait timed out\n", > > crtc->base.id, crtc->name); > > -- > > 2.20.1 > > -- > Ville Syrjälä > Intel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
