linux-kernel - Re: disabling CONFIG_LED_CLASS (SND_HDA_CODEC

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Message-ID: <d8e450ef-cde9-b799-88e9-8ed9940b95fe@xs4all.nl>
Date:   Mon, 19 Oct 2020 10:35:12 +0200
From:   Udo van den Heuvel <udovdh@...all.nl>
To:     Takashi Iwai <tiwai@...e.de>, Randy Dunlap <rdunlap@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-leds@...r.kernel.org, Dan Murphy <dmurphy@...com>,
        moderated for non-subscribers <alsa-devel@...a-project.org>
Cc:     Pavel Machek <pavel@....cz>
Subject: Re: disabling CONFIG_LED_CLASS (SND_HDA_CODEC_REALTEK)

People,

At https://www.kernel.org/doc/html/latest/leds/leds-class.html we can
read that the LEDS code supposedly optimizes away when certain
conditions are met.
Especially the Realtek HDA driver *unconditionally* (as found in 5.9.1)
*wants* to enable LED functionality.
I.e.: if this blockade is lifted in the source tree then I can live with
the 'is optimized out' predictions, assuming that gcc (from Fedora 32)
can do this.
So the request is clear; we're almost there.
Please make it so that the compiler can do the 'optimize away' work bij
changing a tad in the Realtek HDA driver, along the lines of the patch
sent to me earlier or something even more beautiful.

Thanks in advance and kind regards,
Udo



On 14-10-2020 10:37, Pavel Machek wrote:
> On Wed 2020-10-14 10:34:21, Udo van den Heuvel wrote:
>> On 14-10-2020 10:27, Pavel Machek wrote:
>>>> One should have thought about stuff beforehand.
>>>
>>> We did. And decided this is best solution.
>>
>> Then the thought process went awry.
>>
>>>> The non-selectability is not my fault.
>>>
>>> It also does not affect you in any way.
>>
>> It does.
>> /boot fills up even sooner thanks to this unused code.
>> Compiles last longer because of this unused code.
> 
> Have you measured how much slower and how much bigger it is? Do you
> understand that you propose to make source code bigger and slower to
> compile for everyone else?
> 
> You are filling my inbox.
> 
>>> Feel free to go to the mic LED discussion to see why we did it like
>>> this. Then you can come up with better solution for problem at hand.
>>
>> I did not think of forcing code onto somebody. Someone else did.
>> This is effectively the effect of the LEDs thing.
> 
> Without understanding what was decided and why, this discussion is not
> useful.
> 
> 
> 									Pavel
>