Re: [REGRESSION/PATCH] acpi: blacklist win8 OSI for ASUS Zenbok Prime UX31A

From: Felipe Contreras
Date: Wed Jul 31 2013 - 07:32:56 EST

On Wed, Jul 31, 2013 at 12:14 AM, Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote:
> On Tue, Jul 30, 2013 at 07:11:06PM -0500, Felipe Contreras wrote:
>> No, the ACPI driver is exposing a backlight interface, which has a
>> defined stable API.
> From the ACPI spec:
> 'The OEM may define the number 0 as "Zero brightness" that can mean to
> turn off the lighting (e.g. LCD panel backlight) in the device.'
> There's no mechanism for an OS to know whether or not a firmware
> implementation will actually turn the backlight off at 0, so there's no
> way the OS can define the lowest backlight state as anything other than
> "May or may not turn the screen off".

Yes there is; quirks.

Felipe Contreras
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