Re: [PATCH v2] serial: Poll USB devices if usbX serial port is missing

[Andrei Borzenkov <arvidjaar@gmail.com>]

21.11.2016 17:05, Joonas Lahtinen пишет:
> On pe, 2016-11-18 at 15:21 +0300, Andrei Borzenkov wrote:
>> On Fri, Nov 18, 2016 at 1:36 PM, Joonas Lahtinen
>>>
>>> v2:
>>> - Use grub_term_poll_usb to avoid module dependency (Andrei)
>>>
>>
>> Hmm ... note that terminal_input/terminal_output also auto-load
>> modules that handle serial ports. So this still will not be
>> equivalent, it will require user to manually pre-load USB. Did you
>> actually test this version of patch? Do you pre-load USB modules
>> somewhere?
> 
> Nope, I took your word literally and just changed the function.

Looking more closely, only top-level modules are autoloaded anyway, like
"serial" itself; low level drivers are not, at least as far as I can
tell. In your case "serial" is pulled in by using command, so it should
be no change.

> Assuming it's a rather direct replacement. Excuse for that.
> 

Could you confirm that your last version works for you? Could you give
more details about your configuration, in particular, how you load
necessary modules (if you load them)? What USB serial driver you use?

>>
>> The problem is, infrastructure to handle auto-load lists currently
>> belongs to normal mode, while serial may sensibly be used before
>> normal is loaded. Not sure what we can do here.
> 
> I think this is getting more important when we're seeing increasing
> amount of devices without even an internal serial port.
> 
> Sounds to me like pulling the auto-loading out of just normal mode
> would make sense?
> 
> Regards, Joonas
>