2005/12/30, Alan Stern <[EMAIL PROTECTED]>:
> On Fri, 30 Dec 2005, David Brownell wrote:
>
> > > OK, let's assume I have suspended a mouse device. If I move it, it
> > > wakes up the hcd. The hcd got an interrupt and in the interrupt
> > > handler I only raise the C_PORT_SUSPEND field in the port status
> > > change bits. Khubd notices this change and only asks for the root hub
> > > to clear the C_PORT_SUSPEND bit. Should I resume the bus when clearing
> > > this bit ?
> >
> > It's physically impossible to have the bus suspended while some
> > port on it is active. I think that answers your question. ;)
>
> The question was phrased a little vaguely.
>
yeah, sorry for that it was just before starting the last weekend of the year
> If the mouse device is suspended and the bus is active, then khubd will
> see the C_PORT_SUSPEND flag and will call remote_wakeup() to finish
> resuming the mouse. It doesn't just clear the flag.
>
ok, but where is the hcd supposed to wake up the device here ? I don't
think it's done when getting the remote wakeup interrupt because we
should wait for the device to release the bus...then khubd will see
the C_PORT_SUSPEND flag and clear it. The device is still suspended.
Eventually khubd will call remote_wakeup, which will do a
usb_get_status. This last call will fail since the device is not
resumed...
> On the other hand, suppose the mouse and the bus are both suspended.
> When you move the mouse the HCD will get an interrupt and see that a
> remote wakeup request was received. Then the HCD should call
> usb_hcd_resume_root_hub() to tell khubd to re-activate the bus. Once
> that's done, khubd will see the C_PORT_SUSPEND bit and proceed as
> described above.
>
Let say that my hcd has only one port. In both cases you described,
can the hcd call usb_hcd_resume_root_hub() and raise C_PORT_SUSPEND
flag when getting the remote wakeup interrupt ?
Thanks
--
Franck
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