On Wed, Jul 31, 2013 at 12:46:04PM -0500, Felipe Contreras wrote: > That doesn't change the fact that you were wrong, and there *is* > actually a way. The fact that you don't want to go there doesn't mean > it's not there. A quirk list will be incomplete, and as such there's no way to guarantee whether or not a value of 0 will turn off the backlight. This is why the interface doesn't make that guarantee, and why any userspace that depends upon that behaviour is behaving incorrectly. > Here's another: device tree. There's no functional distinction between device tree and a quirk list on x86 - they're both static data sources provided by something other than the system firmware. As a result, they will both be incomplete. > There are ways to provide a consistent backlight interface to user-space. No, there aren't. What you *can* do is propose to change the ABI description for the sysfs backlight interface such that any system where 0 turns off the backlight is considered buggy, but that won't make those systems vanish. A good interface doesn't promise things it can't guarantee, so I'd expect that any such proposal would be rejected. -- Matthew Garrett | mjg59@xxxxxxxxxxxxx -- 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
