Am Montag, 30. Januar 2012, 11:14:12 schrieb Bjørn Mork:
> But if we want the main driver to support autosuspending an active
> device by using remote wakeup, then we need to add some support to
> cdc-wdm for sharing the flag. One simple way would be to add a counter
> and an interface function to be used by the main driver when it wants
> the flag set/cleared. Something like (but with locking added...):
>
> int usb_cdc_wdm_remote_wakeup(struct usb_interface *intf, bool on)
> {
> struct wdm_device *desc = wdm_find_device(intf);
>
> if (on) {
> if (!desc->remote_wakeup++)
> intf->needs_remote_wakeup = 1;
> } else {
> if (!--desc->remote_wakeup)
> intf->needs_remote_wakeup = 0;
> }
> return desc->remote_wakeup;
> }
>
>
> What do you think? Just document that any driver which uses cdc-wdm as
> a subdriver cannot make use of remote wakeup for now? Or add some
> interface like the above? Or something else?
Counters are generally the preffered solution to such problems. You'd better
do it in usbcore and provide three helper functions and a spinlock (or make
it atomic). Then you need to go through all drivers, but this is the cleanest solution
in the long run.
Regards
Oliver
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