Re: TTY loosing data with u_serial gadget

From: Felipe Balbi
Date: Fri Mar 18 2011 - 13:12:16 EST


(please don't top-post)

On Fri, Mar 18, 2011 at 05:35:56PM +0100, Stefan Bigler wrote:
> Thanks for your quick answer. Meanwhile we ported our board to 2.6.38.
> We recognize the same problem again.
> I had also a look at the relevant fixes, a lot is done but I could not find
> the required protection of the attribute receive_room.
> I added a printk in case of failure were receive_room shows more
> space that is really available in the queue and also used.
> The printk is attached below and also the log.
> Regards
> Stefan
> Log:
> flush_to_ldisc, receive_room to small count=201, receive_room=287,
> real_room=0
> flush_to_ldisc, receive_room to small count=225, receive_room=1031,
> real_room=0
> flush_to_ldisc, receive_room to small count=33, receive_room=4095,
> real_room=0

I had the same problem while I was working at Nokia developing the N900.
I even sent a patch (twice) with Alan Cox on the loop but nothing has
happened. The patch might still be floating on the archives but
essentially it would make ->receive_buf() return the amount of received
bytes (as IMHO it should be done).

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