ACPI / video: Add a parameter to not register the backlight sysfs interface
ACPI / video: Add a parameter to not register the backlight sysfs interface

On some systems acpi-video backlight is broken in the sense that it cannot
control the brightness of the backlight, but it must still be called on
resume to power-up the backlight after resume.

This commit allows these systems to work by going through all the usual
backlight control moves, while not registering a sysfs backlight
interface.

This commit also adds a quirk enabling this parameter on Toshiba Portege
R830 systems which are known to be affected by this.

I wish there was a better way to deal with this, but we've been unable to
find one.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=21012
Link: https://bugs.freedesktop.org/show_bug.cgi?id=82634
Reported-and-tested-by: Sylvain Pasche <b2b27d5a1046096d30c1447ece3c22f9728637fb@gmail.com>
Signed-off-by: Hans de Goede <9fa1be1a5b5729e4c6b404f34c9ce49ff4882fd8@redhat.com>
Acked-by: Aaron Lu <e835aaae27ef45c770cbc83733586d01aadc3a43@intel.com>
Signed-off-by: Rafael J. Wysocki <27ffc44a8ec6a212fba98cfc3246c6ce8ab131e0@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs