]> nv-tegra.nvidia Code Review - linux-3.10.git/commit
ACPI video: Don't export sysfs backlight interface if query _BCL fail
authorDanny Kukawka <dkukawka@suse.de>
Tue, 3 Jul 2007 05:33:53 +0000 (01:33 -0400)
committerLen Brown <len.brown@intel.com>
Tue, 3 Jul 2007 05:33:53 +0000 (01:33 -0400)
commitf70ac0e9651aa8c07dffe72a44872f92054d42c3
treec748973de21f228021e270cb5764029641d4d501
parent23b0f015bf2c050b8b5399430ca64e1b3398cf76
ACPI video: Don't export sysfs backlight interface if query _BCL fail

Currently the acpi video module export the backlight interface to sysfs
also if acpi_video_device_lcd_query_levels() fails to read _BLC method
(e.g.  because the method is not available).  In this case the userspace
don't know which brightness level are supported and can't set a brightness
level (echo return with: "write error: Invalid Argument").  This happend
e.g.  on a ASUS RF1 (correct supported by the asus-laptop module).

The video module should not export the backlight interface if query _BLC fail,
because you can't set anything from userspace and this make it useless.

http://bugzilla.kernel.org/show_bug.cgi?id=8375

Signed-off-by: Danny Kukawka <dkukawka@suse.de>
Acked-by: Luming Yu <luming.yu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
drivers/acpi/video.c