[linux-pm] [RFC] Tying sysfs "wakeup" file to platform-level handler

[Deepak Saxena]

On Nov 24 2008, at 16:34, Alan Stern was caught saying:
> On Mon, 24 Nov 2008, Deepak Saxena wrote:
> 
> > Ack. This is what we are already doing.  The decision on whether or 
> > not a device should wake us up from suspend is handle via OHM on the 
> > XO and we set the OLPC-specific flags in /sys/power/wakeup_events as 
> > there is no standard way to specify wakeup events from userland.
> > 
> > My proposal uses the existing sysfs interface to connect into a platform 
> > level handler that can set the appropriate low-level HW bits. The
> > decision of whether or not to enable the device's wakeup capability
> > would still be left to user space. 
> 
> Then I must have misunderstood the point of your earlier message.  Are
> you saying that the real problem is to tie the existing
> /sys/devices/.../power/wakeup flags into your platform handler?

ACK.

> The sources you listed (ac_power, battery_state, and so on) are all 
> pretty much platform-level entities to begin with.  Their drivers must 
> already contain or communicate with a fair amount of platform-level 
> code.  So why should there be any trouble about adding a new 
> communication channel for wakeup settings?

Because some of the drivers we are using are generic and I do not want
to put a bunch of platform-specific code in there.  Let's look at the PS2 
driver for example. We use the generic i8042 driver and I would like
to be able to use /sys/bus/platform/devices/i8042/power/wakeup to set
wakeup enable on mouse or keyboard input so I need a way to trigger 
an EC mask update on a write to that file. 

Maybe there is some other way to do this that I don't quite grok?
Right now, the i8042 device does not have the can_wakeup flag set
so writing either "enabled" or "disabled" leads to -EINVAL.

~Deepak

-- 
 Deepak Saxena  http://www.greenbasement.info
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