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Subject: Re: [PATCH 1/2] x86: Remove led/gpio setup from pcengines platform
 driver
To:     Ed W <lists@wildgooses.com>,
        "Enrico Weigelt, metux IT consult" <lkml@metux.net>,
        linux-kernel@vger.kernel.org
Cc:     fe@dev.tdt.de, "Enrico Weigelt, metux IT consult" <info@metux.net>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        platform-driver-x86@vger.kernel.org
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From:   Hans de Goede <hdegoede@redhat.com>
Message-ID: <d0d91191-cad2-94a1-6373-0f3ff4e38376@redhat.com>
Date:   Wed, 14 Oct 2020 13:29:39 +0200
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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