Linux LED subsystem development
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From: Pavel Machek <pavel@ucw.cz>
To: Hans de Goede <hdegoede@redhat.com>
Cc: "Marek Behún" <kabel@kernel.org>,
	linux-leds@vger.kernel.org, alsa-devel@alsa-project.org,
	"Takashi Iwai" <tiwai@suse.de>
Subject: Re: [PATCH v2] leds: trigger: audio: Add an activate callback to ensure the initial brightness is set
Date: Tue, 23 Feb 2021 10:12:30 +0100	[thread overview]
Message-ID: <20210223091230.GI9750@amd> (raw)
In-Reply-To: <20210221115208.105203-1-hdegoede@redhat.com>

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Hi!

> Some 2-in-1s with a detachable (USB) keyboard(dock) have mute-LEDs in
> the speaker- and/or mic-mute keys on the keyboard.
> 
> Examples of this are the Lenovo Thinkpad10 tablet (with its USB kbd-dock)
> and the HP x2 10 series.
> 
> The detachable nature of these keyboards means that the keyboard and
> thus the mute LEDs may show up after the user (or userspace restoring
> old mixer settings) has muted the speaker and/or mic.
> 
> Current LED-class devices with a default_trigger of "audio-mute" or
> "audio-micmute" initialize the brightness member of led_classdev with
> ledtrig_audio_get() before registering the LED.
> 
> This makes the software state after attaching the keyboard match the
> actual audio mute state, e.g. cat /sys/class/leds/foo/brightness will
> show the right value.

Makes sense.

> +++ b/drivers/leds/trigger/ledtrig-audio.c
> @@ -6,10 +6,33 @@
>  #include <linux/kernel.h>
>  #include <linux/leds.h>
>  #include <linux/module.h>
> +#include "../leds.h"
>  
> -static struct led_trigger *ledtrig_audio[NUM_AUDIO_LEDS];
>  static enum led_brightness audio_state[NUM_AUDIO_LEDS];
>  
> +static int ledtrig_audio_mute_activate(struct led_classdev *led_cdev)
> +{
> +	led_set_brightness_nosleep(led_cdev, audio_state[LED_AUDIO_MUTE]);
> +	return 0;
> +}

Is mute_activate called from atomic context?

Best regards,
								Pavel

-- 
http://www.livejournal.com/~pavelmachek

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  reply	other threads:[~2021-02-23  9:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-21 11:52 [PATCH v2] leds: trigger: audio: Add an activate callback to ensure the initial brightness is set Hans de Goede
2021-02-23  9:12 ` Pavel Machek [this message]
2021-02-23  9:52   ` Hans de Goede
2021-02-24  7:58 ` Takashi Iwai

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