On Monday 20 March 2006 8:59 am, Alan Stern wrote:
> There are other times when the UDC driver might not disable endpoints,
> however. For example, when the cable is unplugged (a disconnect event).
> The gadget API doesn't specify whether endpoints are automatically
> disabled by the UDC driver when a disconnect occurs...
Actually, that's implicit in the usb_ep_enable() writeup:
while it is enabled, an
endpoint may be used for i/o until the driver receives a disconnect() from
the host or until the endpoint is disabled.
Though that could stand to be re-worded, since it's not actually the host
which provides the disconnect notification, it's the transceiver (which
detects VBUS dropping below a threshold of 0.2V or somesuch). Yes, some
systems don't actually have such notifications -- no comparator, or even
a GPIO hooked up to trigger on the falling edge of VBUS -- but that sort
of design limitation is pretty much board-specific. In those cases the
endpoints get disabled as part of the usb reset issued during the next
enumeration.
- Dave
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