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

Fabio Comolli
2010-09-05T08:26:29Z

Hi.

On Sun, Sep 5, 2010 at 12:44 AM, Sitsofe Wheeler <sitsofe@yahoo.com> wrote:
> 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).

Well, this is very strange. I also own an EeePC 900 (i915 of course)
and I don't have this problem at all, nor I need the patch. Actually I
run a plain 2.6.36-rc3 and it works perfectly.

I use the latest userspace available, with xorg 1.9 and Intel video
driver v. 2.12 (Archlinux testing repositories).

Which kernel / userspace are you using?

>
> --
> Sitsofe | http://sucs.org/~sits/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>

Regards,
Fabio