Re: [PATCH] USB: serial: xr: Add TIOCGRS485 and TIOCSRS485 ioctls

[Jarkko Sonninen]

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.

    - Jarkko