[Nouveau] [PATCH] drm/nouveau/disp: use drm_kms_helper_connector_hotplug_event()

[Lyude Paul]

On Wed, 2023-06-21 at 22:13 +0000, Simon Ser wrote:
> Hi Lyude!
> 
> On Wednesday, June 21st, 2023 at 23:56, Lyude Paul <lyude at redhat.com> wrote:
> 
> > > -	if (changed)
> > > +	if (changed == 1)
> > > +		drm_kms_helper_connector_hotplug_event(first_changed_connector);
> > > +	else if (changed > 0)
> > >  		drm_kms_helper_hotplug_event(dev);
> > 
> > I'm curious if you think there might be an advantage to doing this per-
> > connector even with multiple connectors? Seems like we could do that if we
> > stored changed connectors as a bitmask.
> 
> I believe firing off multiple per-connector uevents would be worse than a
> single per-device uevent because user-space would see intermediate states
> instead of an atomic change.
> 
> Let's say I have 3 connectors connected, and different settings set in my
> compositor when 1, 2 or 3 screens are connected. Let's say an unplug
> disconnects 2 monitors at the same time. With a single uevent, the compositor
> refreshes the whole device state, and then applies the 1-screen settings. With
> 2 uevents (one for each connector), the compositor refreshes the first
> disconnected connector state, then applies the 2-screen settings, then
> refreshes the second disconnected connector state, then applies the 1-screen
> settings. Applying the 2-screen settings might cause an unnecessarily glitchy
> intermediate state, where windows move around, modesets are performed, user
> configured commands are run, just to un-do everything right after.
> 
> I hope this makes sense,
> 

Hi! Seems fine to me :)

Reviewed-by: Lyude Paul <lyude at redhat.com>

Let me know if you need me to push it to drm-misc

> Simon
> 

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat