Date: Sat, 5 May 2007 22:52:41 +0100
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Oliver Neukum <oliver@neukum.org>
Cc: Paul Fulghum <paulkf@microgate.com>,
       Antonino Ingargiola <tritemio@gmail.com>,
       linux-usb-users@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [SOLVED] Serial buffer corruption [was Re: FTDI usb-serial
 possible bug]
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On Sat, 5 May 2007 20:07:15 +0200
Oliver Neukum <oliver@neukum.org> wrote:

> Am Samstag, 5. Mai 2007 18:36 schrieb Alan Cox:
> > > In the serial driver this usually just results in dropping
> > > RTS to signal the remote end to stop sending. The serial
> > > driver always immediately gives receive data to the tty buffering
> > > without regard to the throttled state.
> > > 
> > > I would argue that cdc-acm should do the same as the serial driver.
> > 
> > This is a bug in cdc-acm really. It should not double buffer, but to be
> > fair to the authors prior to the new tty buffering it *had* to do this.
> 
> Hi,
> 
> should I understand this so that, if tty_buffer_request_room() returns
> less than requested, the rest of the data should be dropped on the
> floor?

If it returns NULL then either there is > 64K buffered (we can adjust
that if anyone shows need - its just for sanity) or the system is out of
RAM. 

Alan
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