Re: [RFC 1/2] n_tty: fix dropped output characters

[One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>]

On Mon, 14 Apr 2014 15:05:49 +0200
Oliver Neukum <oneukum@suse.de> wrote:

> On Mon, 2014-04-14 at 13:53 +0100, One Thousand Gnomes wrote:
> > On Fri, 11 Apr 2014 11:41:24 +0200
> > Johan Hovold <jhovold@gmail.com> wrote:
> > 
> > > Fix characters being dropped by n_tty_write() due to a failure to
> > > check the return value of tty_put_char() in do_output_char().
> > > 
> > > Characters are currently being dropped by write if a tty driver claims
> > > to have write room available, but still fails to buffer any data
> > 
> > Your driver is buggy. If you advertise a buffer you must honour it and
> > neither shrink nor revoke it.
> 
> Is that a general rule or does it apply only till the next write?

Its a general rule. If you've advertised 5 bytes then you can only
advertise 0 after 5 bytes have been sent your way (or a hangup etc
occurred).

Alan