Re: [PATCH] samsung-laptop: unregister ACPI video module for some well known laptops

[Corentin Chary <corentin.chary@xxxxxxxxx>]

On Tue, Mar 27, 2012 at 1:21 PM, Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote:
> On Tue, Mar 27, 2012 at 11:11:18AM +0200, Corentin Chary wrote:
>> Matthew, is this one ok ? I really hope this patch can go in 3.4 so we
>> don't introduce a regression for old laptops.
>
> Yes, I've got this now.
>
> Thanks,


A user just found a DSDT which is broken by this way of doing things
(this is not really a regression since it was also broken before).

_BCL contains a wierd "Or (VDRV, 0x02, VDRV)".
So if you call _BLC once (video.ko will), it set a flag that affect
the behavior of all backlight related stuff, and it breaks
samsung-laptop's backlight even if samsung-laptop unload the acpi
backlight.
Using acpi_backlight=vendor solves that since it prevents the module
from being loaded. My previous patch also fix that since it use
acpi_backlight= mechanism.

Do you think using acpi_backlight=vendor is a good enought solution
here ? Should we use my first patch instead ?


-- 
Corentin Chary
http://xf.iksaif.net

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