On Tue, Jan 09, 2018 at 12:45:30AM +0300, Mikhail Zaytsev wrote:
> On Mon, 8 Jan 2018 16:28:58 +0100 Johan Hovold <johan@xxxxxxxxxx> wrote:
>
> > On Mon, Jan 08, 2018 at 11:33:32AM +0100, Oliver Neukum wrote:
> > > Am Samstag, den 06.01.2018, 20:14 +0300 schrieb Mikhail Zaytsev:
> > > > The patch removes unused TIOCSSERIAL ioctl case and adds the default block
> > > > to the switch. This will make the ioctl return -ENOTTY to user space (e.g.
> > > > setserial), because TIOCSSERIAL really isn't supported for these devices
> > > > currently.
> > >
> > > Hi,
> > >
> > > this will break software that is now running on these devices,
> > > won't it? Do you know why those devices basically ignore the
> > > ioctl?
> >
> > Yeah, that was my initial reactions as well, but then again, any sane
> > user space cannot rely on these ioctl being implemented for all tty
> > devices.
> >
> > I did some digging now and these (dummy) ioctl implementations where
> > added by commit 2f430b4bbae7 ("USB: ark3116: Add TIOCGSERIAL and
> > TIOCSSERIAL ioctl calls.") back in 2006. This in turn appears to have
> > been triggered by a change in a user space tool, wvdial, which started
> > erroring out if either was missing.
> >
> > I found a couple of bug reports about that through google, and looking
> > at the wvstreams (library) code now, it looks like the issue has indeed
> > been resolved by handling errors more gracefully (e.g. just logging
> > them).
> >
> > So I'm willing to give this a try, and if anyone complains later we add
> > back (or implement) TIOCSSERIAL.
> >
>
> Thanks Johan. I looked the commit 2f430b4bbae7. Author just did a cut'n'paste
> from other USB serial drivers. I think that it would be better remove
> the TIOCGSERIAL implementation too.
I've applied this one now after adding some of the backstory from above
to the commit message.
Thanks,
Johan
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