linux-kernel - Re: disabling CONFIG_LED_CLASS (SND_HDA_CODEC

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Message-ID: <s5hblh5mele.wl-tiwai@suse.de>
Date:   Wed, 14 Oct 2020 09:49:49 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Randy Dunlap <rdunlap@...radead.org>
Cc:     Udo van den Heuvel <udovdh@...all.nl>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-leds@...r.kernel.org, Dan Murphy <dmurphy@...com>,
        Pavel Machek <pavel@....cz>,
        moderated for non-subscribers <alsa-devel@...a-project.org>
Subject: Re: disabling CONFIG_LED_CLASS (SND_HDA_CODEC_REALTEK)

On Wed, 14 Oct 2020 07:54:15 +0200,
Randy Dunlap wrote:
> 
> On 10/13/20 10:16 PM, Udo van den Heuvel wrote:
> > On 14-10-2020 07:07, Randy Dunlap wrote:
> >> On 10/13/20 9:56 PM, Udo van den Heuvel wrote:
> > 
> >>> I.e.: it looks like I will lose some funcionality when I disable
> >>> SND_HDA_CODEC_REALTEK.
> >>
> >> OK. At present you can't have it both ways, i.e., SND_HDA_CODEC_REALTEK
> >> with no LEDS. That driver apparently wants LEDS.
> > 
> > Thanks but why have I gone for years without LEDS?
> > I do not need LEDS, I do not want LEDS, I do not have LEDS (that are
> > visible, usable, etc).
> > 
> > Please make this selectable instead of forcing more bulk into my kernel.
> > 
> > Kind regards,
> > Udo
> 
> Hi Takashi,
> 
> Regarding
> commit 7cdf8c49b1df0a385db06c4f9a5ba1b16510fdcc
> Author: Takashi Iwai <tiwai@...e.de>
> Date:   Thu Jun 18 13:08:31 2020 +0200
>     ALSA: hda: generic: Add a helper for mic-mute LED with LED classdev
> 
> and this Kconfig entry:
> 
> config SND_HDA_CODEC_REALTEK
> 	tristate "Build Realtek HD-audio codec support"
> 	select SND_HDA_GENERIC
> 	select SND_HDA_GENERIC_LEDS
> 
> it seems that LED support is not always wanted (please see above).
> I.e., user(s) would like to build a kernel without LED support at all.
> 
> Can you make it a build option?

Something like this?


Takashi

---
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1390,6 +1390,11 @@ menuconfig EXPERT
 	  environments which can tolerate a "non-standard" kernel.
 	  Only use this if you really know what you are doing.
 
+config SUPERHACKER
+	bool "Rule the world" if EXPERT
+	help
+	  You are allowed to break things at your own risk.
+
 config UID16
 	bool "Enable 16-bit UID system calls" if EXPERT
 	depends on HAVE_UID16 && MULTIUSER
--- a/sound/pci/hda/Kconfig
+++ b/sound/pci/hda/Kconfig
@@ -94,7 +94,7 @@ config SND_HDA_PATCH_LOADER
 config SND_HDA_CODEC_REALTEK
 	tristate "Build Realtek HD-audio codec support"
 	select SND_HDA_GENERIC
-	select SND_HDA_GENERIC_LEDS
+	select SND_HDA_GENERIC_LEDS if !SUPERHACKER
 	help
 	  Say Y or M here to include Realtek HD-audio codec support in
 	  snd-hda-intel driver, such as ALC880.
@@ -115,7 +115,7 @@ comment "Set to Y if you want auto-loading the codec driver"
 config SND_HDA_CODEC_SIGMATEL
 	tristate "Build IDT/Sigmatel HD-audio codec support"
 	select SND_HDA_GENERIC
-	select SND_HDA_GENERIC_LEDS
+	select SND_HDA_GENERIC_LEDS if !SUPERHACKER
 	help
 	  Say Y or M here to include IDT (Sigmatel) HD-audio codec support in
 	  snd-hda-intel driver, such as STAC9200.
@@ -160,7 +160,7 @@ comment "Set to Y if you want auto-loading the codec driver"
 config SND_HDA_CODEC_CONEXANT
 	tristate "Build Conexant HD-audio codec support"
 	select SND_HDA_GENERIC
-	select SND_HDA_GENERIC_LEDS
+	select SND_HDA_GENERIC_LEDS if !SUPERHACKER
 	help
 	  Say Y or M here to include Conexant HD-audio codec support in
 	  snd-hda-intel driver, such as CX20549.
--- a/sound/pci/hda/hda_generic.h
+++ b/sound/pci/hda/hda_generic.h
@@ -354,11 +354,29 @@ unsigned int snd_hda_gen_path_power_filter(struct hda_codec *codec,
 void snd_hda_gen_stream_pm(struct hda_codec *codec, hda_nid_t nid, bool on);
 int snd_hda_gen_fix_pin_power(struct hda_codec *codec, hda_nid_t pin);
 
+#ifdef CONFIG_SND_HDA_GENERIC_LEDS
 int snd_hda_gen_add_mute_led_cdev(struct hda_codec *codec,
 				  int (*callback)(struct led_classdev *,
 						  enum led_brightness));
 int snd_hda_gen_add_micmute_led_cdev(struct hda_codec *codec,
 				     int (*callback)(struct led_classdev *,
 						     enum led_brightness));
+#else /* CONFIG_SND_HDA_GENERIC_LEDS */
+static inline int
+snd_hda_gen_add_mute_led_cdev(struct hda_codec *codec,
+			      int (*callback)(struct led_classdev *,
+					      enum led_brightness))
+{
+	return -ENODEV;
+}
+
+static inline int
+snd_hda_gen_add_micmute_led_cdev(struct hda_codec *codec,
+				 int (*callback)(struct led_classdev *,
+						 enum led_brightness))
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_SND_HDA_GENERIC_LEDS */
 
 #endif /* __SOUND_HDA_GENERIC_H */