Re: [PATCH v3 3/3] ALSA: hda: add support for Huawei WMI micmute LED

From: Pavel Machek <pavel@ucw.cz>
To: Takashi Iwai <tiwai@suse.de>
Cc: Ayman Bagabas <ayman.bagabas@gmail.com>,
	alsa-devel@alsa-project.org, Hui Wang <hui.wang@canonical.com>,
	Andy Shevchenko <andy@infradead.org>,
	Darren Hart <dvhart@infradead.org>,
	Jaroslav Kysela <perex@perex.cz>,
	Kailang Yang <kailang@realtek.com>,
	linux-kernel@vger.kernel.org,
	platform-driver-x86@vger.kernel.org
Subject: Re: [PATCH v3 3/3] ALSA: hda: add support for Huawei WMI micmute LED
Date: Tue, 20 Nov 2018 10:36:10 +0100	[thread overview]
Message-ID: <20181120093610.GF16916@amd> (raw)
In-Reply-To: <s5hbm6kf6gi.wl-tiwai@suse.de>

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On Tue 2018-11-20 10:23:25, Takashi Iwai wrote:
> On Tue, 20 Nov 2018 10:10:39 +0100,
> Pavel Machek wrote:
> > 
> > On Tue 2018-11-20 08:07:09, Takashi Iwai wrote:
> > > On Tue, 20 Nov 2018 00:57:13 +0100,
> > > Pavel Machek wrote:
> > > > 
> > > > > +#if IS_ENABLED(CONFIG_HUAWEI_LAPTOP)
> > > > > +#include <linux/platform_data/x86/huawei_wmi.h>
> > > > > +
> > > > > +static int (*huawei_wmi_micmute_led_set_func)(bool);
> > > > > +
> > > > 
> > > > So we should not be doing this.
> > > > 
> > > > Thinkpad ACPI module exports its LEDs there, for example.
> > > 
> > > Both thinkpad_acpi and dell_laptop provide the interface to HD-audio
> > > in the very same way like this.
> > 
> > Not good :-(. Please don't add new ones, general purpose LEDs should
> > really use LED subsystem.
> 
> What's the problem with this approach?

You have general-purpose LED, yet you are treating it as "something
special". That means ugly code (quoted above) and lack of flexibility.

For example, if my notebook lacks HDD LED, I can use scrollock LED for
that instead. Or, in reverse way, maybe "mic mute" LED is not useful
for me, and I'd like to use it for notifications instead.

(If the LED was driven by hardware, and always reflected microphone
status, that would be different. But that's not the case AFAICT).

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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