patch: acpi usermode suspend API change

Nate Lawson nate at
Thu Jun 21 19:51:48 UTC 2007

Lars Engels wrote:
> On Sun, Jun 17, 2007 at 10:13:34AM -0700, Nate Lawson wrote:
>> This patch updates the user API for acpi suspend in a number of ways.
>> * /etc/rc.suspend,rc.resume are always run, no matter the source of the
>> suspend event
>> * suspend now requires positive user acknowledgement.  If a user program
>> wants to cancel the suspend, they can.  If one of the user programs
>> hangs or doesn't respond within 10 seconds, the system suspends anyway.
>> * /dev/apm is clonable, allowing multiple listeners for suspend events.
>>  In the future, xorg-server can use this to be informed about suspend
>> even if there are other listeners (i.e. apmd).
>> The API changes are intended to be MFCd and hence are minimal.
>> * Two new ACPI ioctls:  REQSLPSTATE and ACKSLPSTATE.  Request begins the
>> process of suspending by notifying all listeners.  acpi is monitored by
>> devd(8) and /dev/apm listener(s) are also counted.  Users register their
>> approval or disapproval via Ack.  If anyone disapproves, suspend is vetoed.
>> * Binary compat is preserved in that old user programs or kernel modules
>> (yeah, right) that called the API can still do so.  A message is printed
>> once that this interface is deprecated.
>> * acpiconf gains the -k flag to ack the suspend request.  This flag is
>> undocumented on purpose since it's only used by /etc/rc.suspend.  It is
>> not intended to be a permanent change and will be removed once a better
>> power API is implemented.
>> These patches have been successfully tested for about a week through
>> suspend/resumes and various usermode programs, including patches to
>> xorg-server.
>> The eventual goal is to improve subr_power to be a more generic central
>> power management interface to user and kernel providers.  powerd(8)
>> might start managing profiles similar to apmd(8).  I don't know yet and
>> there isn't time to do that.  This patch provides a reasonable interface
>> for now and eliminates some serious weaknesses, especially in that
>> pressing a sleep button did not guarantee rc.suspend would run before
>> sleeping.
>> Comments welcome, patches are for 6.x and 7.x.
>> -- 
>> Nate
> Nate, 
> thanks for your patch. 
> But after applying it on a recent -Current I get a lot of kernel messages
> like these:
> Jun 21 17:48:27 maggie kernel: apm34 opened clone 0xc457fd00
> Jun 21 17:48:27 maggie kernel: apm34 closed clone 0xc457fd00
> Jun 21 17:48:32 maggie kernel: apm35 opened clone 0xc457ee40
> Jun 21 17:48:32 maggie kernel: apm35 closed clone 0xc457ee40
> Jun 21 17:48:37 maggie kernel: apm36 opened clone 0xc457ec40
> Jun 21 17:48:37 maggie kernel: apm36 closed clone 0xc457ec40
> Jun 21 17:48:42 maggie kernel: apm37 opened clone 0xc457fc40
> Jun 21 17:48:42 maggie kernel: apm37 closed clone 0xc457fc40
> Jun 21 17:48:47 maggie kernel: apm38 opened clone 0xc433b6c0
> Jun 21 17:48:47 maggie kernel: apm38 closed clone 0xc433b6c0
> Jun 21 17:48:52 maggie kernel: apm39 opened clone 0xc433b240

Thanks for testing! Those were there to assist in debugging if people
had any problems.

> Additionally, pressing the power button only generates this:
> Jun 21 17:50:03 maggie kernel: acpi: request to enter state S5 failed
> I need to run 'shutdown -p ' to power the system down.

This was already fixed in the updated patch that I plan to commit today.
 It's attached or you can just wait for the commit to get it.

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