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Date:   Mon, 13 Mar 2023 21:18:40 +0100
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Subject: Re: [PATCH] USB: serial: xr: Add TIOCGRS485 and TIOCSRS485 ioctls
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jarkko Sonninen <kasper@iki.fi>
Cc:     Johan Hovold <johan@kernel.org>, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20230313010416.845252-1-kasper@iki.fi>
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From:   Oliver Neukum <oneukum@suse.com>
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On 13.03.23 16:50, Greg Kroah-Hartman wrote:
> On Mon, Mar 13, 2023 at 05:07:59PM +0200, Jarkko Sonninen wrote:

>> Using ENOTTY breaks all other tty ioctls.
> 
> What other tty ioctls?
> 
> confused,
> 

This is one of those handlers which simulate OO inheritance in C.
You can implement any IOCTL in the driver. If you do not, you
give back -ENOICTLCOMMAND. Any other error means that you did
implement it and an error occured in the method.

	HTH
		Oliver