On Fri, Oct 21, 2016 at 12:35:44PM +0300, Ville Syrjälä wrote: > On Thu, Oct 20, 2016 at 07:31:53PM -0700, Manasi Navare wrote: > > Hi Ville, > > > > I have implemented the code that we discussed where if the link training > > fails, it would validate the modes on the new constraints and call > > an atomic helper like drm_atomic_helper_connector_modeset() to redo > > a modeset for the same mode. The two patches for this implemnetation is > > are: > > > > http://paste.ubuntu.com/23357104/ > > http://paste.ubuntu.com/23357105/ > > > > With this I can successfully trigger the modeset and retrain the link > > at lower link rate. But I am getting a warning during intel_audio_codec_enable() > > in intel_enable_ddi() during the commit phase on SKL. > > Following is the dmesg log: > > > > http://paste.ubuntu.com/23357075/ > > > > After further looking at it, I see that this calls drm_select_eld() function > > that throws a warning if the mode_config mutex and modeset locks are held. > > You get the warn when they're *not* held. And checking for the > mode_config.mutex here looks like a bug. We call that during a modeset, > so if we get there through the atomic ioctl as opposed to a legacy > setcrtc we will not be holding the mode_config.mutex. > > Walking the connector list with just the connection mutex should be safe > in theory. Although last I looked it was still racy as hell, but as I > said, in theory. > > We could probably drop the connector list walk from there entirely since > we should know exactly which connector's eld we want. Yes, lets please avoid connector_list walks if we know what we're doing. Which we really should here with link training. Also spoiler on connector_list locking: It's probably going to be an entirely new locking scheme for this one, independent of either mode_config.mutex and mode_config.connection_mutex. Most likely invovling some kind of rcu. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
