On Sat, 12 May 2007, Soeren Sonnenburg wrote: > Dear all, > > I've realized using the great powertop ( http://www.linuxpowertop.org/ ) > that loading the appletouch driver (and touching it once) makes consumes > about 0.3 W even when not touching the pad. As rmmod'ing appletouch > fixes this I wonder why the driver does not do this alone. So my > question is what does one have to do to convert a driver (such as > appletouch) to make use of usb autosuspend except for > > .supports_autosuspend = 1
One has to add appropriate calls to usb_autopm_get_interface() and usb_autopm_put_interface(), or equally well, to usb_autopm_enable() and usb_autopm_disable(). One might also need to set intf->needs_remote_wakeup to 1 in the probe routine. > While we are at it usb related powerhogs on this macbook pro are > uhci_hcd (usb keyboard) and usb_hcd_poll_rh_status (rh_timer_func) > too... They would use less power if the UHCI host controller were suspended. But obviously it cannot be suspended while devices attached to it (such as the USB keyboard and the appletouch device) remain active. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
