On Mon, 26 Dec 2005, Paul Ionescu wrote: > > There's one other thing to note: Power off is different from suspend. > > Many USB host controllers are not capable of turning off the power to > > their ports. (All external hubs are supposed to have this capability, > > however.) So if you have a USB device plugged directly into your > > computer, you may indeed be able to suspend it but you probably won't be > > able to power it off. > > > > So then, when I "eject" an USB device in M$ Windows, what actually happens is > not a "power off" > the device, but a "suspend" the device ?
I think that's right. I haven't run an actual test. Probably what really happens is that Windows disables the USB port, but to the device that's indistinguishable from a suspend. > Is there any way I can tell if my USB controller is able to power off or not ? > Can it be seen in the output of the lsusb -v ? Or in some /sys files ? If you turn on the CONFIG_USB_DEBUG option, that information will show up in the kernel log when the controller is initialized. Alan Stern ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
