On Tue, 2008-12-30 at 18:34 +0800, Richard Purdie wrote: > On Wed, 2008-12-24 at 11:07 +0800, Zhang Rui wrote: > > bd->props.brightness is a cached value. > > the current code has some potential problems when poking the > > backlight I/F. > > > > For example, > > 1. set the brightness level to 5 via sysfs I/F > > 2. set the backlight to another level via the procfs, > > 3. setting it back to 5 doesn't work because bd->props.brightness > > is still 5. > > > > http://bugzilla.kernel.org/show_bug.cgi?id=12249 > > The root of the problem here is that there are two interfaces > controlling the same piece of hardware. Personally, I'd like to see the > proc interfaces to backlights depreacated but we do need to make them > work I guess. The real bug looks like the proc interface should update > props.brightness for that hardware... It is also ok that the props.brightness is also updated when the proc interface is called. But in such case the "brightness" won't display the user requested value. Sometimes the brightness will be changed by BIOS and there is no notification event. In such case the props.brightness can't be updated. If we want to update the brightness, the request will have no effect. So IMO it will be more appropriate that brightness is always updated when poking "brightness". Thanks. Yakui > > Cheers, > > Richard > -- 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
