Re: [PATCH] sony-laptop: allow complex per-value input/output validation

["Mattia Dongili" <malattia@linux.it>]

On Tue, February 13, 2007 9:59 am, Richard Purdie said:
> On Tue, 2007-02-13 at 09:47 +0100, Mattia Dongili wrote:
>> On Tue, February 13, 2007 5:55 am, Len Brown said:
>> > On Monday 12 February 2007 16:01, Mattia Dongili wrote:
>> >> allows consistency between the sony-laptop
>> >> specific 'brightness_default' and the backlight subsystem 0-based
>> >> 'brightness'.
>> >
>> > Why do we need to have "sony-laptop specific 'brightness_default'" --
>> > is that a shortcoming of the backlight subsystem?
>>
>> It depends on how do you see it :)
>> brightness_default is the value that brightness will have at the next
>> (and
>> later) reboot and it's currently handled as a platform_device attribute.
>> It would be nice anyway if one such attribute could be added to the
>> backlight subsystem (I'll provide patches - added rpurdie to the Cc
>> list)
>> in order to standardize its behavior/interface.
>
> The backlight class doesn't really have any reason to know anything
> about defaults. The current behaviour is that if you want it at a
> certain 'default' brightness, you set it to this after you register the
> device. Some devices don't want the brightness changed and want to use
> whatever it was set to originally. In the case of some other drivers,
> you can't read the brightness value.

well this is actually hardware driven, the brightness_default in
sony-laptop only exposes a DSDT method to set this value.
So it's actually one more feature, not a software trick :)
I admit the attribute could be better named 'poweron_brightness'.

> With any patches, please keep in mind the changes in
> http://git.o-hand.com/?p=linux-rpurdie-backlight;a=shortlog;h=for-mm as
> I've separated out the ops functions from the actual device specific
> data.

Yep, thanks.
-- 
mattia
:wq!