This revamps the apm-emulation code to get suspend notifications
regardless of what way pm_suspend() was invoked, whether via the
apm ioctl or via /sys/power/state. Also do some code cleanup and
add comments while at it.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
The APM emulation is currently broken as a result of commit
8314418629
"Freezer: make kernel threads nonfreezable by default"
that removed the PF_NOFREEZE annotations from apm_ioctl() without adding
the appropriate freezer hooks. Fix it and remove the unnecessary variable flags
from apm_ioctl().
Special thanks to Franck Bui-Huu <vagabon.xyz@gmail.com> for pointing out the
problem.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Franck Bui-Huu <vagabon.xyz@gmail.com>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Len Brown <len.brown@intel.com>
Move the definition of 'struct pm_ops' and related functions from <linux/pm.h>
to <linux/suspend.h> .
There are, at least, the following reasons to do that:
* 'struct pm_ops' is specifically related to suspend and not to the power
management in general.
* As long as 'struct pm_ops' is defined in <linux/pm.h>, any modification of it
causes the entire kernel to be recompiled, which is unnecessary and annoying.
* Some suspend-related features are already defined in <linux/suspend.h>, so it
is logical to move the definition of 'struct pm_ops' into there.
* 'struct hibernation_ops', being the hibernation-related counterpart of
'struct pm_ops', is defined in <linux/suspend.h> .
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves. This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.
It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.
The patch causes all kernel threads to be nonfreezable by default (ie. to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE. It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear. Additionally, it updates documentation to
describe the freezing of tasks more accurately.
[akpm@linux-foundation.org: build fixes]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently ARM and MIPS both have nearly identical copies of the APM
emulation code in their arch code. Add yet another copy of it to
drivers char and make it selectable through SYS_SUPPORTS_APM_EMULATION.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
