Re: [PATCH] ACPI: disable the ACPI backlight control on laptops with buggy _BCL methods

Zhang Rui
2009-01-09T01:52:39Z

On Fri, 2009-01-09 at 09:18 +0800, Matthew Garrett wrote:
> On Fri, Jan 09, 2009 at 09:13:38AM +0800, Zhang Rui wrote:
>
> >
> > _BQC returns 3 when the actual backlight level is 0x50.
> > We only know that the value returned by _BQC is invalid but we never
> > know the value is an index until we see the _AML code.
>
> If the value returned is less than the smallest value in the _BLC block,
> then it's an index. This heuristic will never break a standards
> compliant system, but (to the best of my knowledge) will work with any
> of these systems that we're currently aware of.
>
well, this does work, but a little bit ugly...
The ACPI backlight control on boxes with such _BCL/_BCM/_BQC methods
implemented surely doesn't work before.
so IMO disabling it again is not that bad. :)

thanks,
rui