Re: [RFC] What are the goals for the architecture of an in-kernel IR system?

Jarod Wilson
2010-04-09T12:59:55Z

On Fri, Apr 09, 2010 at 06:50:26AM -0400, Andy Walls wrote:
> On Fri, 2010-04-09 at 08:21 +0100, James Hogan wrote:
> > Hi,
> >
> > On Thursday 25 March 2010 14:42:33 Mauro Carvalho Chehab wrote:
> > > Comments?
> >
> > I haven't seen this mentioned yet, but are there any plans for a sysfs
> > interface to set up waking from suspend/standby on a particular IR scancode
> > (for hardware decoders that support masking of comparing of the IR data), kind
> > of analagous to the rtc framework's wakealarm sysfs file?
>
> This requires support at the hardware level. (You can't have CPU code
> running to decode IR pulses when your CPU is "asleep".)
>
> I know of two video chips supported under linux that provide such a
> function.
>
> Wake-up from IR for these chips will rely on the kernel PCIe or USB
> infrastructure supporting PCIe or USB Power Managment Events from
> hardware. It will take a huge amount of work and time to get the
> respective linux video drivers to properly support suspend/resume
> properly.
>
> If you're waiting for me to get that working, I'll advise you to plan on
> getting off the couch and pushing the power switch for some time to
> come. ;)
>
>
>
>
> The MCE-USB, I *speculate*, can perform wakes. It's driver would need
> to support that, if it can.

Yep, it can perform wakes, and the current lirc_mceusb does support it,
though it requires some screwing around with echoing something into
somewhere in sysfs (for the usb controller its attached to) to enable it,
from what I recall... Making it Just Work would be a good idea.

--
Jarod Wilson
jarod@redhat.com