Re: [TECH TOPIC] Driver probe fails and register succeeds

Shuah Khan
2022-06-24T15:55:54Z

On 6/24/22 12:31 AM, Greg KH wrote:
> On Thu, Jun 23, 2022 at 05:05:30PM -0600, Shuah Khan wrote:
>> I have been debugging a driver probe failure and noticed that driver gets
>> registered even when driver probe fails. This is not a new behavior. The
>> code in question is the same since 2005.
>
> As others have pointed out, this is "by design". Probe is independent
> of a driver registering in the kernel (i.e. module_init()) and should
> never determine if a module is to not be loaded or not.
>
> That was part of the explicit design of the driver model we did back in
> the 2.5 kernel days. We don't want to go back to the old style of "if a
> module can not find a device to control, fail to load" model, it does
> not work well for a variety of reasons.
>

Thank you - this is helpful.

> So it sounds like the driver is working properly for this portion of it,
> we can discuss the specifics of it on the subsystem-specific mailing
> list to find out of anything else is currently wrong with it, but I
> don't think this needs to be a tech topic from what I can tell.
>

Thank you. Makes sense. This driver probe failure is a bug that needs to
be fixed. I have a few fixes to send.

thanks,
-- Shuah