Re: [PATCH 1/2] cdc-acm: do not reset notification buffer index upon urb unlinking

[Oliver Neukum]

On Sa, 2018-09-22 at 22:11 +0200, Tobias Herzog wrote:
> Resetting the write index of the notification buffer on urb unlink (e.g.
> closing a cdc-acm device from userspace) may lead to wrong interpretation
> of further received notifications, in case the index is not 0 when urb
> unlink happens (i.e. when parts of a notification already have been
> transferred). On the device side there is no "reset" of the notification
> transimission and thus we would get out of sync with the device.

Hi,

you are right, when you are describing the problem. The fix seems to me
to fix a part, albeit a large part of the issue. As far as I can tell,
the transfer could be partially succesful, meaning that the driver
loses a part in the middle of the notification.

	Regards
		Oliver