Power Mangement Interfaces
jordan.crouse at amd.com
Sat Mar 31 11:16:13 EDT 2007
On 31/03/07 02:18 +0200, Johannes Berg wrote:
> On Fri, 2007-03-30 at 17:57 -0600, Jordan Crouse wrote:
> I think the sources file isn't really useful, a
> grep -l 1 /sys/power/wakeup/*
> should do.
I was just trying to be friendly to folks who may be used to the ACPI
> About different possible states: I think each of those can have
> different possible wakeup sources, ACPI can afaik go to S4 and still be
> able to configure the wakeup sources. So I suppose this really needs to
> be something like /sys/power/wakeup/<state>/<event> then where <state>
> is one of (currently) "mem", "disk" and "standby". And then change the
> interface of pm_register_wakeup_source to include the state.
> Also, I'm not sure I like the interface with the name of the wakeup
> event set by the platform driver. That will probably lead to
> inconsistencies, a centrally maintained file with items could be nicer.
I considered that - but different platforms and PM methods may have
radically different events (will WLAN ever be an event that any other x86
platform would use)?
So I thought it best that we allow the platform driver to provide the
name, and then enforce consistancy from the developers.
> About test mode: there is such a thing for suspend to disk. In fact, if
> you just want to test driver suspend you could use that. See
> the /sys/power/disk file.
Yeah - I stole the idea from there. That only works when you go down the
suspend to disk path, though, and I wanted to make sure we were going down
our own STR path. We go all the way into our sleep methods (in fact, I used
it to catch an early bug where we were not restoring the stack correctly in
the lowlevel resume function). I think there are other uses for the test
mode that even extend into the firmware - consider a clocks on test method
that goes as far as setting up the wake events, but never actually turn
off the power rails.
Thanks for your comments.
Senior Linux Engineer
Advanced Micro Devices, Inc.
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