Re: [PATCH] usbnet: Activate halt interrupt endpoint before re-submit URB

Am Mittwoch, 20. Juni 2012, 12:15:25 schrieb Ming Lei:

On Wed, Jun 20, 2012 at 4:58 PM, Oliver Neukum [off-list ref] wrote:

quoted

Am Mittwoch, 20. Juni 2012, 10:07:55 schrieb Ming Lei:

quoted

BTW, maybe it is better to add below

    usbnet_defer_kevent(dev, EVENT_STS_HALT);

for -EPIPE returned from usb_urb_submit if it will be resent.

Why? If it failed once it'll probably also fail the next time.

-EPIPE just means the endpoint is halted, either from usb_urb_submit
or urb->status, so the HALT should be cleared in the situation.

It probably was halted and cleared. However that you cleared
a halt doesn't mean that the reason for stalling went away.
So you must cope with an endpoint being halted again right after
it was cleared.

quoted

In that case we'd need to do something more intrusive
like resetting the device, but that cannot be done well
in the generic usbnet part.

IMO, resetting is not needed for -EPIPE, but may be needed for
-EPROTO failure.

We don't need it for a single failure, but what else would we do
if we keep getting -EPIPE?

	Regards
		Oliver