Messages in this thread | | | Date | Wed, 09 May 2012 13:40:27 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: [PATCH]: In kernel hibernation, suspend to both |
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On 05/09/2012 03:52 AM, Bojan Smojver wrote:
> Hi Rafael, > > Here is the same thing, this time with signed off. Looks like all the > memory used for hibernation is being released before power_down(), so I > guess we should be good. The patch is against linux-next. > > ------------------------------ > Enable suspend to both for in-kernel hibernation. > > It is often useful to suspend to memory after hibernation image has been > written to disk. If the battery runs out or power is otherwise lost, the > computer will resume from the hibernated image. If not, it will resume > from memory and hibernation image will be discarded. > > Signed-off-by: Bojan Smojver <bojan@rexursive.com> > --- > Documentation/power/swsusp.txt | 5 +++++ > kernel/power/hibernate.c | 36 ++++++++++++++++++++++++++++++++++++ > kernel/power/power.h | 3 +++ > kernel/power/swap.c | 28 ++++++++++++++++++++++++++++ > 4 files changed, 72 insertions(+), 0 deletions(-) > > diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt > index ac190cf..92341b8 100644 > --- a/Documentation/power/swsusp.txt > +++ b/Documentation/power/swsusp.txt > @@ -33,6 +33,11 @@ echo shutdown > /sys/power/disk; echo disk > /sys/power/state > > echo platform > /sys/power/disk; echo disk > /sys/power/state > > +. If you would like to write hibernation image to swap and then suspend > +to RAM (provided your platform supports it), you can try > + > +echo suspend > /sys/power/disk; echo disk > /sys/power/state > + > . If you have SATA disks, you'll need recent kernels with SATA suspend > support. For suspend and resume to work, make sure your disk drivers > are built into kernel -- not modules. [There's way to make > diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c > index e09dfbf..3b5726f 100644 > --- a/kernel/power/hibernate.c > +++ b/kernel/power/hibernate.c > @@ -5,6 +5,7 @@ > * Copyright (c) 2003 Open Source Development Lab > * Copyright (c) 2004 Pavel Machek <pavel@ucw.cz> > * Copyright (c) 2009 Rafael J. Wysocki, Novell Inc. > + * Copyright (C) 2012 Bojan Smojver <bojan@rexursive.com> > * > * This file is released under the GPLv2. > */ > @@ -44,6 +45,9 @@ enum { > HIBERNATION_PLATFORM, > HIBERNATION_SHUTDOWN, > HIBERNATION_REBOOT, > +#ifdef CONFIG_SUSPEND > + HIBERNATION_SUSPEND, > +#endif > /* keep last */ > __HIBERNATION_AFTER_LAST > }; > @@ -572,6 +576,10 @@ int hibernation_platform_enter(void) > */ > static void power_down(void) > { > +#ifdef CONFIG_SUSPEND > + int error; > +#endif > + > switch (hibernation_mode) { > case HIBERNATION_REBOOT: > kernel_restart(NULL); > @@ -581,6 +589,25 @@ static void power_down(void) > case HIBERNATION_SHUTDOWN: > kernel_power_off(); > break; > +#ifdef CONFIG_SUSPEND > + case HIBERNATION_SUSPEND: > + error = suspend_devices_and_enter(PM_SUSPEND_MEM);
I can imagine running into a host of problems here, since the suspend sequence is not carried out fully, from the beginning.
For example, this will skip sending out the PM_SUSPEND_PREPARE and the PM_POST_SUSPEND notifiers. Worse, we actually send out the PM_HIBERNATION_PREPARE and PM_POST_HIBERNATION notifiers and then do a suspend instead, underneath!
(Similar cases for the rest of the notifiers sent during suspend vs hibernation).
Don't we need to handle such things properly, in order to make suspend-to-both work reliably?
Regards, Srivatsa S. Bhat
> + if (error) { > + if (hibernation_ops) > + hibernation_mode = HIBERNATION_PLATFORM; > + else > + hibernation_mode = HIBERNATION_SHUTDOWN; > + power_down(); > + } > + /* > + * Restore swap signature. > + */ > + error = swsusp_unmark(); > + if (error) > + printk(KERN_ERR "PM: Swap will be unusable! " > + "Try swapon -a.\n"); > + return; > +#endif
> }
> kernel_halt(); > /*
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