Re: [PATCH v2] Documentation usb serial: fixed how to provide vendor and product id

[Johan Hovold <johan@kernel.org>]

On Mon, Apr 13, 2015 at 10:09:27PM +0200, Marek Belisko wrote:
> From: "H. Nikolaus Schaller" <hns@goldelico.com>
> 
> While trying to test a Cinterion GSM/GPS/3G module I had reconfigured
> the USB interface by mistake and therefore needed to run a different
> USB driver than CDC-ACM. It turned out that I need the "usbserial" driver.
> 
> This file is an official description how to use it: Documentation/usb/usb-serial.txt
> 
> But it is outdated. The parameters vendor= and product= are only available
> if compiled as a kernel module and have been superseded by a /sys interface.
> 
> Here was the solution:
> 
> https://bbs.archlinux.org/viewtopic.php?id=175499
> 
>   insmod usbserial vendor=0x#### product=0x####
> 
> becomes (first #### is vendor, second is product)
> 
>   modprobe usbserial
>   echo #### #### >/sys/bus/usb-serial/drivers/generic/new_id
> 
> This patch changes the documentation file to describe the modern variant.
> Please note that the old one still works (if compiled as module).
> 
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> Signed-off-by: Marek Belisko <marek@goldelico.com>
> ---
> 
> changes from v1:
> - add modern variant with /sys as preferred but also old one works so
>   keep it in documentation (was removed in first version which was not correct)

Thanks for the update. Much better.

>  Documentation/usb/usb-serial.txt | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/usb/usb-serial.txt b/Documentation/usb/usb-serial.txt
> index 947fa62..3f31c96 100644
> --- a/Documentation/usb/usb-serial.txt
> +++ b/Documentation/usb/usb-serial.txt
> @@ -465,12 +465,15 @@ Generic Serial driver
>    device, and does not support any kind of device flow control. All that
>    is required of your device is that it has at least one bulk in endpoint,
>    or one bulk out endpoint. 
> -  
> -  To enable the generic driver to recognize your device, build the driver
> -  as a module and load it by the following invocation:
> -	insmod usbserial vendor=0x#### product=0x####
> +
> +  To enable the generic driver to recognize your device, provide
> +	echo #### #### >/sys/bus/usb-serial/drivers/generic/new_id
>    where the #### is replaced with the hex representation of your device's
>    vendor id and product id.

Could you use distinct symbols for vendor and product if (e.g. <vid>
and <pid>) to make it clear which is which?

> +  If the driver is compiled as a module, you can either
> +	modprobe usbserial

This isn't needed.

> +  or, you can also provide the parameters directly

This could be "you can also provide one id when loading the module".

> +	insmod usbserial vendor=0x#### product=0x####

Thanks,
Johan