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

[Dr. H. Nikolaus Schaller]

Hi Johan,

Am 30.03.2015 um 09:45 schrieb Johan Hovold <johan@xxxxxxxxxx>:

> On Sat, Mar 28, 2015 at 02:37:57PM +0100, Marek Belisko wrote:
>> From: "H. Nikolaus Schaller" <hns@xxxxxxxxxxxxx>
>> 
>> While trying to test the Pyra GSM/GPS/3G module I had reconfigured
>> the USB interface by mistake and therefore needed to run a different
>> USB driver than CSC-ACM. It turned out that I need the "usbserial" driver.
> 
> CDC-ACM

oh, thanks. There is always at least one more typo in any document…

> 
>> 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 But it is outdated.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 no longer
>> available since ca. 3.12 which means that documentation is lagging behind
>> quite some time.
> 
> This is simply not true. The vendor and module parameters are still
> there for usbserial (i.e. the generic driver).
> 
> Would you mind updating this patch to document the sysfs-method as an
> alternative instead? Using sysfs is preferred as that functionality can
> be used with any usb-serial driver and the drivers can also be compiled
> in.

Hm. For me it did not work as described and therefore I searched for
and found the solution cited below, which appears to confirm that it does
not work any more. Only with these hints to use the /sys approach I
could make it working immediately.

Therefore I assumed that the documentation is outdated.

But it might also be a hidden bug with the parameter passing.
I had tested on 4.0-rc3.

I can try a little more but it might be waste of time to find out why the old
does not work, if there is a preferred method now.

> 
>> 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 as needed.
>> 
>> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
>> Signed-off-by: Marek Belisko <marek@xxxxxxxxxxxxx>
>> ---
>> Documentation/usb/usb-serial.txt | 12 +++++++-----
>> 1 file changed, 7 insertions(+), 5 deletions(-)
>> 
>> diff --git a/Documentation/usb/usb-serial.txt b/Documentation/usb/usb-serial.txt
>> index 947fa62..9f184d8 100644
>> --- a/Documentation/usb/usb-serial.txt
>> +++ b/Documentation/usb/usb-serial.txt
>> @@ -466,11 +466,13 @@ Generic Serial driver
>>   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####
>> -  where the #### is replaced with the hex representation of your device's
>> -  vendor id and product id.
>> +  To enable the generic driver to recognize your device, configure
>> +  USB_SERIAL_GENERIC=y and build the driver as a module. Then load it by the
> 
> You don't need to build the driver as a module when using the sysfs
> method.

Ok, that is right and my formulation is too narrow on that.

So we just s/ as a module//.

> 
>> +  following invocation:
>> +	modprobe usbserial
>> +	echo #### #### >/sys/bus/usb-serial/drivers/generic/new_id
>> +  where the the first #### is replaced with the hex representation of your
>> +  device's vendor id and the second #### by the product id.
>> 
>>   This driver has been successfully used to connect to the NetChip USB
>>   development board, providing a way to develop USB firmware without
> 
> Thanks,
> Johan

Thanks as well,
Nikolaus


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