[Intel-gfx] [PATCH 1/2] drm/i915: Try to use fast+narrow link on eDP again and fall back to the old max strategy on failure

[Kai-Heng Feng]

On Tue, May 11, 2021 at 2:06 AM Albert Astals Cid <aacid at kde.org> wrote:
>
> Yes, I also have the same.
>
> I git bisected that and found this to be the cause, i started a new email thread because i couldn't find this email ^_^

Should be fixed by
https://cgit.freedesktop.org/drm-tip/commit/?id=acca7762eb71bc05a8f28d29320d193150051f79

Kai-Heng

>
> Cheers,
>   Albert
>
> El dilluns, 10 de maig de 2021, a les 10:07:33 (CEST), Emanuele Panigati va escriure:
> > Hi,
> >   on my Dell XPS 15 9570 laptop I might have a regression with Arch Linux
> > (kernel 5.12.2-arch1-1: during boot the laptop monitor goes black while
> > external monitors still works...
> >
> >
> > Panich
> >
> >
> > Il giorno lun 11 gen 2021 alle ore 19:28 Ville Syrjälä <
> > ville.syrjala at linux.intel.com> ha scritto:
> >
> > > On Thu, Jan 07, 2021 at 08:20:25PM +0200, Ville Syrjala wrote:
> > > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > >
> > > > Some new eDP panels don't like to operate at the max parameters, and
> > > > instead we need to go for an optimal confiugration. That unfortunately
> > > > doesn't work with older eDP panels which are generally only guaranteed
> > > > to work at the max parameters.
> > > >
> > > > To solve these two conflicting requirements let's start with the optimal
> > > > setup, and if that fails we start again with the max parameters. The
> > > > downside is probably an extra modeset when we switch strategies but
> > > > I don't see a good way to avoid that.
> > > >
> > > > For a bit of history we first tried to go for the fast+narrow in
> > > > commit 7769db588384 ("drm/i915/dp: optimize eDP 1.4+ link config
> > > > fast and narrow"). but that had to be reverted due to regression
> > > > on older panels in commit f11cb1c19ad0 ("drm/i915/dp: revert back
> > > > to max link rate and lane count on eDP"). So now we try to get
> > > > the best of both worlds by using both strategies.
> > >
> > > Pushed. Fingers crossed for no regressions...
> > >
> > > --
> > > Ville Syrjälä
> > > Intel
> > >
> >
>
>
>
>