On Sat, 3 Apr 2010, Alan Stern wrote: > > But the microphone device does not suspend and I have to suspend it manually for it to save power (about 1 watt): > > echo suspend > /sys/bus/usb/devices/1-5/power/level > > > > This command used to work for me but now that I am testing the latest Fedora Rawhide (fc13) it is throwing the following error: > > -bash: echo: write error: Invalid argument > > > > Why is this? Would it be a good idea to report this problem in kernel bugzilla? if so, under which component/module?? how can I test if userspace is keeping the device open (maybe pulseaudio)? > > Starting in 2.6.33, the kernel no longer accepts "suspend" as an input > to the power/level attribute. If you want to suspend a device > manually, the easiest way is to unconfigure it: > > echo 0 >/sys/bus/usb/devices/1-5/bConfigurationValue > > Remember first to make a note of what value was originally in that > file, so that you can reconfigure the device later on (by writing the > old value back). Usually the old value will be 1, but not always. I forgot to mention -- you also have to write "auto" to the power/level file, since the default is to keep the device powered on always. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
