Re: USB autosuspend and turning of usb pendrive leds
Hans de Goede <[email protected]>
| Newsgroups | gmane.linux.usb.devel,gmane.linux.kernel |
|---|---|
| Message-ID | <[email protected]> |
Alan Stern wrote: > On Sat, 22 Sep 2007, Hans de Goede wrote: > >> I'm afraid that that doesn't work for usb mass-storage devices. >> >> Here is what I did: >> 1) kill hal >> 2) insert usb stick -> led lights >> 3): >> echo -n 1 > /sys/bus/usb/devices/.../power/autosuspend >> echo -n auto > /sys/bus/usb/devices/.../power/level >> >> 4) wait >> >> Nothing happens, where as sending "suspend" to power/level does turn the led >> off. > > I don't know what went wrong. It works fine on my systems. You did > fill in the correct device path for the "...", right? Yes, the one that comes and goes as I plug in one of the USB-sticks I ue for testing. > And you don't > need the "-n" -- adding it shouldn't matter, but you should try reading > back the contents of those files to make sure the values did get > written correctly. > I did read them back and it did get written correctly. >> Now call me naive, but I would expect a mass-storage devices with no >> partitions mounted to autosuspend when autosuspend is enabled for that device. > > Yes, that is naive. The driver has no way to tell whether or not any > partitions are mounted. Furthermore, you might very well want to > access the raw device without mounting any partitions (database > managers frequently do such things to reduce I/O overhead), in which > case you certainly would not the device to be autosuspended. > How does this relate to your "It works fine on my systems" remark, do I need to do anything other the unmounting the paritions to make the device eligible for autosuspend, like unbind the sd driver or even the usb-storage driver? If so I must say I find that a little counter intuitive. Regards, Hans p.s. As always, please keep me CC-ed, not on the list. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel