Message-ID: <71fd009b-8378-d5b0-5243-5279b2b880ee@iki.fi>
Date:   Mon, 13 Mar 2023 17:07:59 +0200
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Subject: Re: [PATCH] USB: serial: xr: Add TIOCGRS485 and TIOCSRS485 ioctls
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To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Johan Hovold <johan@kernel.org>, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20230313010416.845252-1-kasper@iki.fi>
 <ZA7KIs2jA/acpN9n@kroah.com> <a1ba59be-30aa-08e9-65e7-2c458cc164f9@iki.fi>
 <ZA7Wh2Z/DdKOsOYr@kroah.com>
From:   Jarkko Sonninen <kasper@iki.fi>
In-Reply-To: <ZA7Wh2Z/DdKOsOYr@kroah.com>
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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