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

Sven Joachim
2010-09-04T20:42:52Z

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!

Sven