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! - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
