Date:   Mon, 13 Mar 2023 16:50:03 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Jarkko Sonninen <kasper@iki.fi>
Cc:     Johan Hovold <johan@kernel.org>, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] USB: serial: xr: Add TIOCGRS485 and TIOCSRS485 ioctls
Message-ID: <ZA9GK2bPd9VhomgG@kroah.com>
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On Mon, Mar 13, 2023 at 05:07:59PM +0200, Jarkko Sonninen wrote:
> On 3/13/23 09:53, Greg Kroah-Hartman wrote:
> > On Mon, Mar 13, 2023 at 09:49:26AM +0200, Jarkko Sonninen wrote:
> > > > > +{
> > > > > +	void __user *argp = (void __user *)arg;
> > > > > +
> > > > > +	switch (cmd) {
> > > > > +	case TIOCGRS485:
> > > > > +		return xr_get_rs485_config(tty, argp);
> > > > > +	case TIOCSRS485:
> > > > > +		return xr_set_rs485_config(tty, argp);
> > > > > +	}
> > > > > +	return -ENOIOCTLCMD;
> > > > Wrong ioctl return value :(
> > > What is the correct ioctl error return value ?
> > > ENOIOCTLCMD was used in most places in usb serial as an error return.
> > ENOTTY is the correct one for when an ioctl is not handled by the ioctl
> > call.
> > 
> > thanks,
> > 
> > greg k-h
> 
> Using ENOTTY breaks all other tty ioctls.

What other tty ioctls?

confused,

greg k-h