acer-wmi: fix regression in backlight detection

Currently we disable the Acer WMI backlight device if there is no ACPI
backlight device.  As a result, we end up with no backlight device at all.
 We should instead disable it if there is an ACPI device, as the other
laptop drivers do.  This regression was introduced in 976772e ("Acer-WMI:
fingers off backlight if video.ko is serving this functionality").

Each laptop driver with backlight support got a similar change around
976772e.  The changes to the other drivers look correct; see e.g.
39ae4622 for a similar but correct change.  The regression is also in
2.6.28.

Signed-off-by: Michael Spang <mspang@csclub.uwaterloo.ca>
Acked-by: Thomas Renninger <trenn@suse.de>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Len Brown <len.brown@intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: <stable@kernel.org>		[2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/platform/x86/acer-wmi.c b/drivers/platform/x86/acer-wmi.c
index 94c9f911824ef5b3279205a41a87dd169935f1db..6bcca616a70405bf057520b064a2a29dcf302078 100644 (file)
--- a/drivers/platform/x86/acer-wmi.c
+++ b/drivers/platform/x86/acer-wmi.c
@@ -1297,7 +1297,7 @@ static int __init acer_wmi_init(void)
 
        set_quirks();
 
-       if (!acpi_video_backlight_support() && has_cap(ACER_CAP_BRIGHTNESS)) {
+       if (acpi_video_backlight_support() && has_cap(ACER_CAP_BRIGHTNESS)) {
                interface->capability &= ~ACER_CAP_BRIGHTNESS;
                printk(ACER_INFO "Brightness must be controlled by "
                       "generic video driver\n");