Merge branch 'upstream'

Documentation/feature-removal-schedule.txt

@@ -127,13 +127,6 @@ Who:	Christoph Hellwig <hch@lst.de>
 
 ---------------------------
 
-What:	EXPORT_SYMBOL(lookup_hash)
-When:	January 2006
-Why:	Too low-level interface.  Use lookup_one_len or lookup_create instead.
-Who:	Christoph Hellwig <hch@lst.de>
-
----------------------------
-
 What:	CONFIG_FORCED_INLINING
 When:	June 2006
 Why:	Config option is there to see if gcc is good enough. (in january
@@ -241,3 +234,15 @@ Why:	The USB subsystem has changed a lot over time, and it has been
 Who:	Greg Kroah-Hartman <gregkh@suse.de>
 
 ---------------------------
+
+What:	find_trylock_page
+When:	January 2007
+Why:	The interface no longer has any callers left in the kernel. It
+	is an odd interface (compared with other find_*_page functions), in
+	that it does not take a refcount to the page, only the page lock.
+	It should be replaced with find_get_page or find_lock_page if possible.
+	This feature removal can be reevaluated if users of the interface
+	cannot cleanly use something else.
+Who:	Nick Piggin <npiggin@suse.de>
+
+---------------------------

Documentation/leds-class.txt

@@ -0,0 +1,71 @@
+LED handling under Linux
+========================
+
+If you're reading this and thinking about keyboard leds, these are
+handled by the input subsystem and the led class is *not* needed.
+
+In its simplest form, the LED class just allows control of LEDs from
+userspace. LEDs appear in /sys/class/leds/. The brightness file will
+set the brightness of the LED (taking a value 0-255). Most LEDs don't
+have hardware brightness support so will just be turned on for non-zero
+brightness settings.
+
+The class also introduces the optional concept of an LED trigger. A trigger
+is a kernel based source of led events. Triggers can either be simple or
+complex. A simple trigger isn't configurable and is designed to slot into
+existing subsystems with minimal additional code. Examples are the ide-disk,
+nand-disk and sharpsl-charge triggers. With led triggers disabled, the code
+optimises away.
+
+Complex triggers whilst available to all LEDs have LED specific
+parameters and work on a per LED basis. The timer trigger is an example.
+
+You can change triggers in a similar manner to the way an IO scheduler
+is chosen (via /sys/class/leds/<device>/trigger). Trigger specific
+parameters can appear in /sys/class/leds/<device> once a given trigger is
+selected.
+
+
+Design Philosophy
+=================
+
+The underlying design philosophy is simplicity. LEDs are simple devices
+and the aim is to keep a small amount of code giving as much functionality
+as possible.  Please keep this in mind when suggesting enhancements.
+
+
+LED Device Naming
+=================
+
+Is currently of the form:
+
+"devicename:colour"
+
+There have been calls for LED properties such as colour to be exported as
+individual led class attributes. As a solution which doesn't incur as much
+overhead, I suggest these become part of the device name. The naming scheme
+above leaves scope for further attributes should they be needed.
+
+
+Known Issues
+============
+
+The LED Trigger core cannot be a module as the simple trigger functions
+would cause nightmare dependency issues. I see this as a minor issue
+compared to the benefits the simple trigger functionality brings. The
+rest of the LED subsystem can be modular.
+
+Some leds can be programmed to flash in hardware. As this isn't a generic
+LED device property, this should be exported as a device specific sysfs
+attribute rather than part of the class if this functionality is required.
+
+
+Future Development
+==================
+
+At the moment, a trigger can't be created specifically for a single LED.
+There are a number of cases where a trigger might only be mappable to a
+particular LED (ACPI?). The addition of triggers provided by the LED driver
+should cover this option and be possible to add without breaking the
+current interface.
+