[Intel-gfx] [PATCH] drm: Don't race connector registration

Daniel Vetter daniel at ffwll.ch
Tue Jan 31 07:44:26 UTC 2017

On Mon, Jan 30, 2017 at 08:43:17AM -0800, Dave Hansen wrote:
> On 01/30/2017 01:12 AM, Daniel Vetter wrote:
> > On Thu, Jan 26, 2017 at 12:34:29PM -0800, Dave Hansen wrote:
> ...
> >> And, yeah, I think it just gets the connected status wrong.  The
> >> connector is still there.
> > 
> > Hm, I thought I replied here but I didn't:
> > - Is this just after boot (and then the connector is stuck forever), or
> >   starts to happen after suspend/resume, or some other system change like
> >   that? Or do they just crop up eventually?
> The most consistent thing I do to screw it up is switch systems on my
> DVI KVM switch.  When I switch back to the system in question, it
> doesn't seem to notice the condition.  The connectors eventually show up
> with random combinations of switching to the console (ctrl-alt-f1) and
> back, running xrandr, or running gnome-control-panel and opening the
> Displays applet.

Hm, so is this a dp mst kvm switch (i.e. do the connectors get
hot-added/removed when you plug/unplug that thing)? Or just some other
non-mst switch? I was working under the assumption that this is mst still,
but I've never seen an mst kvm switch.

> I haven't been able to discern any pattern to it.  Sometimes just
> running xrandr fixes it.  Sometimes just opening the control panel.
> Others, I have to do it several times.
> I don't think it shows up if I just leave it for a while.
> > - Does this only happen once the connector is destroyed? Please trace
> >   intel_dp_destroy_mst_connector with something like:
> I'll see if I can gather that.

If it's not mst, then don't bother with this for obvious reasons :-)
Daniel Vetter
Software Engineer, Intel Corporation

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