Re: Wake on USB

[Paul B. <peb...@gm...>]

On 3/27/2011 6:03 PM, Dale Pontius wrote:
> On 03/25/11 18:41, Jarod Wilson wrote:
> <snip>
>> The main goal behind this release is compatibility with all the
>> lirc code that has been merged into the Linux kernel as of
>> around 2.6.36 and on. I've also removed several drivers that I
>> consider completely obsolete and will never update ever again,
>> as they've been superseded by upstream kernel drivers. There will
>> be more chopped out of 0.9.1 as well. :)
>
> Perhaps this is a good place/opportunity to ask this question.  I'm
> using an mceusb IR receiver/remote on a dedicated mythfrontend machine.
>   To make it more appliance-like with faster powerup I suspend instead of
> powering off.
>
> I haven't been able to wake-on-USB with any kernel after the 2.6.32
> series.  I'm currently running 2.6.32-gentoo-r27, and it and every
> kernel before that properly does wake-on-USB.  No kernel beginning with
> 2.6.33 does, and that includes testing 2.6.38 this afternoon.  It also
> includes both Gentoo and vanilla kernels.
>
> I ask here because you're about to remove the lirc drivers that I'm
> using, and I haven't been able to get myself up to 2.6.36 yet, though
> I'd really like to.  I recognize that this issue is not core to lirc,
> though in the lirc community people may be more aware of this kind of
> problem and how to fix it.
>
> Everything in userspace remains unchanged between the various kernels,
> and when I build 2.6.33+ kernels I start with my 2.6.32 config and tweak
> the new stuff, but the old stuff is still essentially there.
>
> One note...  My mceusb IR receiver has an LED that blinks when it
> receives a signal.  When the system is suspended and I press the power
> button, that LED comes on solid until the system has wakened.  When
> suspended with a 2.6.33+ kernel the LED doesn't come on, doesn't even
> blink when the power button is pressed.  I can wake the system with the
> front-panel power button, in any case.

You need to be sure that the power is provided to the device. In the 
past, this was done through /proc/acpi/wakeup. However, with more recent 
kernels, this is done through /sys/devices/*/wakeup. I use the following 
script to enable wakeup when the remote is detected by udev:

#!/bin/sh
################################################################################
# wakeup_enable
################################################################################

devpath=`readlink -f "/sys/${DEVPATH}"`
while echo "${devpath}" | /bin/grep -q '^/sys/devices/' > /dev/null 2>&1 
; do
     if test -e "${devpath}/power/wakeup" ; then
         state=`cat "${devpath}/power/wakeup"`
         if test "x${state}" = "xdisabled" ; then
             echo "enabled" > "${devpath}/power/wakeup"
         fi
     fi
     devpath=`dirname "${devpath}"`
done

exit 0