On Mon, Aug 04, 2014 at 03:50:34PM +0300, Ville Syrjälä wrote: > On Mon, Aug 04, 2014 at 10:10:50AM +0200, Daniel Vetter wrote: > > On Fri, Aug 01, 2014 at 02:55:22PM +0300, Ville Syrjälä wrote: > > > On Thu, Jul 31, 2014 at 08:59:08PM +1000, Dave Airlie wrote: > > > > On 31 July 2014 17:37, Daniel Vetter <daniel@xxxxxxxx> wrote: > > > > > On Thu, Jul 31, 2014 at 1:49 AM, Dave Airlie <airlied@xxxxxxxxx> wrote: > > > > >> Daniel, the only way intel_dp->is_mst can get reset is inside this path. > > > > > > > > > > Ok, so that one should be safe. Then I guess we can just push the > > > > > locking down into the respective non-mst leafs (since atm we do > > > > > link-retraining without any locking, which isn't good). And it needs > > > > > to be dev->mode_config.mutex, not connection mutex. > > > > > > Why that? We can't be doing a modeset w/o connection_mutex so that > > > seems like it should be enough. Well, there's also dpms which leaves > > > the crtc<->encoder<->connector links intact but that too takes > > > connection_mutex currently. > > > > > > > > > > > I'd like to know why we do link training at this point though as well, > > > > adding locking is required of course, I was just going to wrap the > > > > short irq call to the link status check with the lock, but I think it > > > > should be possible to push it down further, > > > > > > I don't really know why the sink generates the hpd when we turn off the > > > port, but that doesn't really matter I think. We need to be prepared for > > > hpds at any time. > > > > > > intel_dp_check_link_status() just checks if there's a crtc, which there > > > is (either the old one or the new one, depending on how far along the > > > modeset path we are I guess), and then it just checks > > > drm_dp_channel_eq_ok() which says false since the link was turned off, > > > and then it proceeds to retrain the link. > > > > > > Maybe it should also check crtc->active? Though that itself won't > > > eliminate the problem unless the locking gets fixed somehow. > > > > We check encoder->connectors_active, which is equivalent. > > Only after intel_sanitize_encoder(). Before that we can have > !crtc->active && encoder->connectors_active. We grab all modeset locks when calling modeset_setup_hw_state, which means no one will ever notice the inconsistent state between state readout and sanitizing it. I think we're safe. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
