Re: [PATCH 1/2] x86: Remove led/gpio setup from pcengines platform driver

[Hans de Goede]

Hi,

On 10/14/20 1:21 PM, Ed W wrote:
> On 14/10/2020 09:41, Hans de Goede wrote:
> > So I have a suggested compromise:
> >
> > Keep the current LED/gpio setup code, but make executing it conditional
> > on the BIOS version and skip the LED/gpio setup when the new BIOS is
> > present to avoid having duplicate LED entries, etc. in that case.
> >
> > I guess this would still break userspace because if I understand things
> > correctly the new ACPI based setup uses different LED names ? That
> > seems unfortunate, but I guess that from the kernel pov we can just
> > blame the BIOS for this, and since we definitely do not want duplicate
> > LED entries for the same LED, this seems the least bad choice.
> >
> > Enrico, would that work for you ?
>
>
> I'm cool with this. Enrico?
>
> I may have some time imminently to have a stab at a new patch. Obviously any help structuring this
> would be appreciated - it feels clumsy using the existing detection mechanism, I think whatever I
> come up with you should kick back and recommend a new board detection structure, but perhaps we can
> shortcut that step with a few comments up front?

I'm afraid I do not have any wisdom to share here. I would use the DMI bios-version
or bios-date strings for the detection, but I guess that is obvious.

Other then I guess I would do a preparation patch restructuring the code so that
the whole conditional part becomes a single if, e.g.:

	if (old_bios()) {
		ret = register_leds_and_gpio_for_old_bios()
		if (ret)
			goto error_cleanup;
	}

So in a separate preparation commit put all the code which you tried to
remove earlier in a single helper function (feel free to pick a different name).

And then in that prep patch the above would look like this:

	ret = register_leds_and_gpio_for_old_bios()
	if (ret)
		goto error_cleanup;

And a follow-up commit adding the new/old bios detection would
introduce the if.

And do the same for the cleanup parts for module unloading.

I hope this helps...

Regards,

Hans