[Intel-gfx] [PATCH] drm/i915: Always wake the device to flush the GTT

[Chris Wilson]

Quoting Daniel Vetter (2017-08-30 14:59:32)
> On Wed, Aug 30, 2017 at 01:56:40PM +0100, Chris Wilson wrote:
> > Quoting Daniel Vetter (2017-08-30 13:23:56)
> > > Or just the need to add a pile more tests to pm_rpm?
> > 
> > No. It's just your regular combinatorial explosion. The approach I would
> > take here would be to register a sysenter callback that attempted to do a
> > rpm suspend (i.e. so ~every ioctl would start from idle, and controlled
> > via the faultinjection framework) and then run the minimal test set that
> > exercises all ioctl paths, and then expand to all driver branches.
> > 
> > First we need coverage feedback.
> 
> What I meant to imply: As long as any display is on we will never rpm
> suspend. Mostly this is the case for CI machines.
> 
> The new testcases I've had in mind would explicitly dpms off the display
> before running a set of gem testcases. We don't want to do that everywhere
> though, because a dpms on/off is very costly.

If no userspace is using the display and we remove fbcon, shouldn't the
kernel be disabling the outputs anyway? There's literally nothing there
to provide display continuity.
-Chris