[PATCH] usb: Make what it takes for "usbkbd" to work in "stdin" clear

[Dragan Simic]

Hello Marek,

On 2025-01-27 22:55, Marek Vasut wrote:
> On 1/19/25 7:50 PM, Dragan Simic wrote:
>> Selecting the CONFIG_SYS_CONSOLE_ENV_OVERWRITE option actually 
>> prevents the
>> CONFIG_USB_KEYBOARD option from working as expected, i.e. USB 
>> keyboards end
>> up not working as console inputs when "usbkbd" is properly specified 
>> as part
>> of the value of the "stdin" environment variable.  Describe this 
>> clearly in
>> the two relevant Kconfig files, to prevent any possible confusion.
>> 
>> In more detail, the console_init_r() function ends up overwriting the 
>> "stdin"
>> environment variable so it contains only the devices available at that 
>> point
>> (which doesn't include "usbkbd"), while the "usb start" operation is 
>> performed
>> much later, at which point the probe_usb_keyboard() function cannot 
>> assign any
>> discovered USB keyboards to the console because "usbkbd" is no longer 
>> present
>> in the "stdin" environment variable.
> 
> Wouldn't it be better to patch console_init_r() , check if "stdin"
> variable contains 'usbkbd' and if so, start USB and register the
> keyboard as stdin device at this point ? This is called after
> relocation, so starting USB should be OK to do here. The behavior
> should then be less confusing to users too.

Please correct me if I'm wrong, but isn't "usb start" deliberately
left to be executed as desired by the supported boards, or as part
of distroboot, i.e. in include/config_distro_bootcmd.h?