[Intel-gfx] [PATCH 2/2] drm/i915: Don't reprobe on resume

[Daniel Vetter]

On Thu, Jul 16, 2015 at 07:41:14PM +0200, Rui Tiago Cação Matos wrote:
> On Thu, Jul 16, 2015 at 5:32 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > On Thu, Jul 16, 2015 at 04:47:51PM +0200, Daniel Vetter wrote:
> >> If we don't force the connector state to unknown there's no reason any
> >> more to force a reprobe. Also no other driver bothers with this, so
> >> probably it's not required - userspace handles lid/resume events
> >> through other channels already.
> >
> > No, we don't. We don't synthesize any events at all for changing
> > connectors whilst suspended
> 
> I haven't tried this patch yet but note that even the current kernel
> (4.1.2) isn't sending HOTPLUG uevents out in precisely that case. It
> would be nice if that got fixed.

You only get a hotplug event when something has actually changed, not for
every suspend/resume.

> > userspace doesn't know about being
> > suspended.
> 
> For GNOME, we just rely on systemd to suspend so we do know when we
> resume and we can easily trigger a reprobe then. It's up to you to
> decide if this should be left to userspace but please
> advertise/document it clearly.

I'm not fully sure, but I think all other drivers don't trigger a probe
over suspend/resume either.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch