[systemd-devel] udev 182: response timeout for request_firmware in module_probe path

[Ming Lei]

On Fri, Aug 24, 2012 at 12:46 AM, Alan Cox <alan at lxorguk.ukuu.org.uk> wrote:
>> IMO, the driver probing path is allowed to sleep, so looks request firmware
>> should be allowed inside .probe().
>
> I'm not convinced about that. It can sleep but its holding various locks
> in most cases, and it looks like that can end up in a complete heap.

Currently, only wait_for_completion() pends in the path of request_firmware
without holding other locks.

>
> By all means *request* the firmware asynchronously in the probe, but
> there needs to be a seperate method somewhere after the probe to finish
> the job once the firmware appears.

Yes, request asynchronously will work and introduce a bit complexity
(but it is not a big deal)

Looks the focus is that why request_firmware can't be used in driver
.probe().

IMO, we should consider that most of drivers call request_firmware
inside its .probe(), and maybe udev need to support the usage.


Thanks,
-- 
Ming Lei