Re: [PATCH] usb: gadget: configfs: Correctly set use_os_string at bind

[William Wu <william.wu@rock-chips.com>]

On 8/22/2025 12:50 PM, Greg KH wrote:
> On Fri, Aug 22, 2025 at 11:36:09AM +0800, William Wu wrote:
>> Once the use_os_string flag is set to true for some functions
>> (e.g. adb/mtp) which need to response the OS string, and then
>> if we re-bind the ConfigFS gadget to use the other functions
>> (e.g. hid) which should not to response the OS string, however,
>> because the use_os_string flag is still true, so the usb gadget
>> response the OS string descriptor incorrectly, this can cause
>> the USB device to be unrecognizable on the Windows system.
>>
>> An example of this as follows:
>>
>> echo 1 > os_desc/use
>> ln -s functions/ffs.adb configs/b.1/function0
>> start adbd
>> echo "<udc device>" > UDC   #succeed
>>
>> stop adbd
>> rm configs/b.1/function0
>> echo 0 > os_desc/use
>> ln -s functions/hid.gs0 configs/b.1/function0
>> echo "<udc device>" > UDC  #fail to connect on Windows
>>
>> This patch sets the use_os_string flag to false at bind if
>> the functions not support OS Descriptors.
>>
>> Signed-off-by: William Wu <william.wu@rock-chips.com>
> 
> What commit id does this fix?
Fixes: 87213d388e92 ("usb: gadget: configfs: OS String support")

Best Regards,
William Wu>
> thanks,
> 
> greg k-h
> 
>