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authorLen Brown <len.brown@intel.com>2011-03-23 02:34:54 -0400
committerLen Brown <len.brown@intel.com>2011-03-23 02:34:54 -0400
commit02e2407858fd62053bf60349c0e72cd1c7a4a60e (patch)
tree0ebdbddc97d3abbc675916010e7771065b70c137 /Documentation/ABI/stable/sysfs-class-backlight
parent96e1c408ea8a556c5b51e0e7d56bd2afbfbf5fe9 (diff)
parent6447f55da90b77faec1697d499ed7986bb4f6de6 (diff)
Merge branch 'linus' into release
Conflicts: arch/x86/kernel/acpi/sleep.c Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'Documentation/ABI/stable/sysfs-class-backlight')
-rw-r--r--Documentation/ABI/stable/sysfs-class-backlight20
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/ABI/stable/sysfs-class-backlight b/Documentation/ABI/stable/sysfs-class-backlight
index 4d637e1c4ff..70302f370e7 100644
--- a/Documentation/ABI/stable/sysfs-class-backlight
+++ b/Documentation/ABI/stable/sysfs-class-backlight
@@ -34,3 +34,23 @@ Contact: Richard Purdie <rpurdie@rpsys.net>
Description:
Maximum brightness for <backlight>.
Users: HAL
+
+What: /sys/class/backlight/<backlight>/type
+Date: September 2010
+KernelVersion: 2.6.37
+Contact: Matthew Garrett <mjg@redhat.com>
+Description:
+ The type of interface controlled by <backlight>.
+ "firmware": The driver uses a standard firmware interface
+ "platform": The driver uses a platform-specific interface
+ "raw": The driver controls hardware registers directly
+
+ In the general case, when multiple backlight
+ interfaces are available for a single device, firmware
+ control should be preferred to platform control should
+ be preferred to raw control. Using a firmware
+ interface reduces the probability of confusion with
+ the hardware and the OS independently updating the
+ backlight state. Platform interfaces are mostly a
+ holdover from pre-standardisation of firmware
+ interfaces.