[Intel-gfx] [PATCH] drm/i915: Disable LVDS while modesetting for HD+ panels

[Takashi Iwai]

At Mon, 2 Jul 2012 19:55:17 +0200,
Daniel Vetter wrote:
> 
> On Mon, Jul 2, 2012 at 7:51 PM, Takashi Iwai <tiwai at suse.de> wrote:
> > It's just for avoiding the possible regressions by this change.
> > We definitely need a fix for HD+ panels ASAP, while other panels work
> > in the current code.  Introducing the extra disable code affecting all
> > laptops sounds too risky for 3.5 kernel, as we can't cover all cases.
> > But for HD+ panels, we did fairly good coverage, as there are still
> > little models.
> >
> > If you find this limitation nonsense and we are brave enough, let's
> > do it without complication.
> 
> Hm, I've hoped I could chicken out and to the non-limited thing for
> 3.6 ... as you say, it's a bit late to do such a change in after -rc5.
> So I guess the question is: How much does not having this patch break
> panels, i.e. can some mad vt-switching restore them or are they
> bricked for good until reset?

On HP laptops I've tested, the screen can be partially recovered from
B/W garbages when you once disable LVDS and enable again.  But then
the screen starts flickering.  And much worse, this flickering remains
even after the cold boot!

I have to put the machine rest for a while to restore the screen
completely.


thanks,

Takashi