power management: remove firmware disk mode
This patch removes the firmware disk suspend mode which is the wrong approach,
it is supposed to be used for implementing firmware-based disk suspend but
cannot actually be used for that.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: <linux-pm@lists.linux-foundation.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Greg KH <greg@kroah.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/power/interface.txt b/Documentation/power/interface.txt
index 74311d7..8c5b41b 100644
--- a/Documentation/power/interface.txt
+++ b/Documentation/power/interface.txt
@@ -18,17 +18,10 @@
/sys/power/disk controls the operating mode of the suspend-to-disk
-mechanism. Suspend-to-disk can be handled in several ways. The
-greatest distinction is who writes memory to disk - the firmware or
-the kernel. If the firmware does it, we assume that it also handles
-suspending the system.
-
-If the kernel does it, then we have three options for putting the system
-to sleep - using the platform driver (e.g. ACPI or other PM
-registers), powering off the system or rebooting the system (for
-testing). The system will support either 'firmware' or 'platform', and
-that is known a priori. But, the user may choose 'shutdown' or
-'reboot' as alternatives.
+mechanism. Suspend-to-disk can be handled in several ways. We have a
+few options for putting the system to sleep - using the platform driver
+(e.g. ACPI or other pm_ops), powering off the system or rebooting the
+system (for testing).
Additionally, /sys/power/disk can be used to turn on one of the two testing
modes of the suspend-to-disk mechanism: 'testproc' or 'test'. If the
@@ -44,16 +37,12 @@
Reading from this file will display what the mode is currently set
to. Writing to this file will accept one of
- 'firmware'
- 'platform'
+ 'platform' (only if the platform supports it)
'shutdown'
'reboot'
'testproc'
'test'
-It will only change to 'firmware' or 'platform' if the system supports
-it.
-
/sys/power/image_size controls the size of the image created by
the suspend-to-disk mechanism. It can be written a string
representing a non-negative integer that will be used as an upper
diff --git a/Documentation/power/states.txt b/Documentation/power/states.txt
index 0931a33..34800cc 100644
--- a/Documentation/power/states.txt
+++ b/Documentation/power/states.txt
@@ -62,17 +62,18 @@
inconvenience, this method requires minimal work by the kernel, since
the firmware will also handle restoring memory contents on resume.
-If the kernel is responsible for persistently saving state, a mechanism
-called 'swsusp' (Swap Suspend) is used to write memory contents to
-free swap space. swsusp has some restrictive requirements, but should
-work in most cases. Some, albeit outdated, documentation can be found
-in Documentation/power/swsusp.txt.
+For suspend-to-disk, a mechanism called swsusp called 'swsusp' (Swap
+Suspend) is used to write memory contents to free swap space.
+swsusp has some restrictive requirements, but should work in most
+cases. Some, albeit outdated, documentation can be found in
+Documentation/power/swsusp.txt. Alternatively, userspace can do most
+of the actual suspend to disk work, see userland-swsusp.txt.
Once memory state is written to disk, the system may either enter a
low-power state (like ACPI S4), or it may simply power down. Powering
down offers greater savings, and allows this mechanism to work on any
system. However, entering a real low-power state allows the user to
-trigger wake up events (e.g. pressing a key or opening a laptop lid).
+trigger wake up events (e.g. pressing a key or opening a laptop lid).
A transition from Suspend-to-Disk to the On state should take about 30
seconds, though it's typically a bit more with the current
diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt
index 0761ff6..c55bd50 100644
--- a/Documentation/power/swsusp.txt
+++ b/Documentation/power/swsusp.txt
@@ -156,8 +156,7 @@
be very careful).
-Q: What is the difference between "platform", "shutdown" and
-"firmware" in /sys/power/disk?
+Q: What is the difference between "platform" and "shutdown"?
A:
@@ -166,11 +165,8 @@
platform: save state in linux, then tell bios to powerdown and blink
"suspended led"
-firmware: tell bios to save state itself [needs BIOS-specific suspend
- partition, and has very little to do with swsusp]
-
-"platform" is actually right thing to do, but "shutdown" is most
-reliable.
+"platform" is actually right thing to do where supported, but
+"shutdown" is most reliable (except on ACPI systems).
Q: I do not understand why you have such strong objections to idea of
selective suspend.
@@ -388,8 +384,8 @@
modes like "suspend-to-RAM" or "standby". (Don't write "disk" to the
/sys/power/state file; write "standby" or "mem".) We've not seen any
hardware that can use these modes through software suspend, although in
-theory some systems might support "platform" or "firmware" modes that
-won't break the USB connections.
+theory some systems might support "platform" modes that won't break the
+USB connections.
Remember that it's always a bad idea to unplug a disk drive containing a
mounted filesystem. That's true even when your system is asleep! The