Re: [PATCH] Revert "drm/i915: fix vblank wait test condition"

Sitsofe Wheeler
2010-09-04T22:45:05Z

On Sat, Sep 04, 2010 at 10:42:46PM +0200, Sven Joachim wrote:
> On 2010-09-04 21:54 +0200, Hugh Dickins wrote:
>
> > On Sat, 4 Sep 2010, Pekka Enberg wrote:
> >> On Sat,  4 Sep 2010 11:17:14 +0300, Pekka Enberg <penberg@kernel.org> wrote:
> >> >> This reverts commit 9559fcdbff4f93d29af04478bbc48294519424f5. The commit causes
> >> >> wrong screen resolution on some i915 machines such as MacBook which is a
> >> >> regression from 2.6.35. The issue has been reported multiple times but no fix
> >> >> has emerged:
> >>
> >> On Sat, Sep 4, 2010 at 12:21 PM, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> >> > NAK. You can't simply hide one bug by introducing a much bigger one.
> >>
> >> Dude, it's a nasty regression from 2.6.35. What exactly are you NAK'ing here?
> >>
> >> > As you have an affected machine, find which wait_for_vblank() needs to be
> >> > replaced with a msleep(20|50).
> >>
> >> The attached patch fixes things here. I'm not a drm developer so I
> >> don't know if it makes technical sense.
> >
> > Many thanks to you, Pekka: I also don't know if it makes technical sense,
> > but it solves the same issue for me, so I can at last use 2.6.36-rc on
> > this laptop.
>
> Helps for me as well, but I cannot judge whether it makes technical
> sense either. Thanks, Pekka!

Sadly this doesn't help my EeePC 900 with an i915 when it is booted with
a battery inside or after doing a suspend to ram (running
modetest/xrandr in these situations says VGA is connected when there
isn't even a cable attached).

--
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