Hi All,

Thanks for your efforts and tips on this.

I am running the following fedora kernel

  2.6.23.1-42.fc8

with CONFIG_USB_SUSPEND=y, and uvcvideo compiled from today's svn head.

When I echo "auto" to the relevant /sys/devices/../power/level, the cam
seems to continue to draw power indefinitely.  As soon as I echo "1"
to /sys/devices/../power/autosuspend, the camera immediately cools, and
the laptop consumes approx 1.4W less power.  I also see the "Suspending
interface" trace message from uvc_driver.c.

Is there something else that needs to be configured before suspend will
be triggered automatically?

Thanks for any tips, and I'm happy to troubleshoot further,

Jason.

On Thu, 2008-01-10 at 20:25 -0800, Brandon Philips wrote:
> On 19:58 Thu 10 Jan 2008, Jason Grant wrote:
> > I rarely use the integrated webcam on my laptop (046d:08c6).  It runs
> > very hot, and I would like to stop it consuming battery power.
> > 
> > It looks like a power-management patch is in the works, however in the
> > interim, I have read that it is possible to power off the camera by
> > doing something like:
> > 
> > echo "0"
> > > /sys/devices/pci0000:00/0000:00:1d.7/usb1/1-5/bConfigurationValue
> > 
> > I have tried this without success (running fedora 8 and latest uvcvideo
> > from svn).  Is there any truth to this?  If not, I am hoping that
> > someone here could provide me with info on how to manually turn this
> > camera off/on.  I will happily write a c program to do this if required.
> 
> The autosuspend code has been added to SVN if you want to test it.
> 
> 0. Recompile with CONFIG_USB_DEBUG if you want to see debugging output
> 1. Locate the device with lsusb
> 2. Go to its sysfs directory
> 3. echo "auto" > power/level
> 4. wait for messages about the device and its root hub being suspended
>    in syslog. It'll take a few seconds (if you have CONFIG_USB_DEBUG)
> 
> e.g.
> 
> ~$ lsusb
> Bus 005 Device 005: ID 046d:0991 Logitech, Inc.
> 
> # echo auto >
> /sys/devices/pci0000\:00/0000\:00\:1d.7/usb5/5-1/power/level
> 
> Cheers,
> 
>       Brandon
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