[Intel-gfx] [PATCH] drm/i915: only disable default vga device

[Emil Velikov]

On Tue, 18 May 2021 at 12:17, Ville Syrjälä
<ville.syrjala at linux.intel.com> wrote:
>
> On Tue, May 18, 2021 at 12:09:56PM +0100, Emil Velikov wrote:
> > Hi Ville,
> >
> > On Mon, 17 May 2021 at 18:24, Ville Syrjälä
> > <ville.syrjala at linux.intel.com> wrote:
> > >
> > > On Sun, May 16, 2021 at 06:14:32PM +0100, Emil Velikov wrote:
> > > > From: Vivek Das Mohapatra <vivek at collabora.com>
> > > >
> > > > This patch is to do with seamless handover, eg when the sequence is
> > > > bootloader → plymouth → desktop.
> > > >
> > > > It switches the vga arbiter from the "other" GPU to the default one
> > > > (intel in this case), so the driver can issue some io().
> > >
> > > I don't understand what this commit message is trying to say.
> > >
> > Bunch of context is lost due to the patch age, so I'm not 100% sure of
> > the actual hardware setup where this occurs.
> > Does the following make sense?
> >
> > Currently on dual GPU systems, we do not get seamless handover as the
> > output flickers during the transition bootloader -> plymouth ->
> > desktop.
> > This happens as a result of switching (via the VGA arbiter) from the
> > "other" GPU back to the default i915 one and issuing io() commands.
>
> Hmm. Does this work?
>
Thanks I'll it give it a try. Might need a few days to find the right
hardware/software combination.

-Emil