Re: [PATCH v3] platform/x86: asus-wmi: fix camera key LED on Zenbook S14

[Ilpo Järvinen]

On Sat, 17 Oct 2026, Zane via B4 Relay wrote:

> From: Zane <git@xxxxxxxxxxxx>
> 
> On some newer Zenbooks (Zenbook S 14 UX5406SA, Zenbook S 16 UM5606WA) the
> camera key turns the camera off in firmware, but the LED on the key never
> lights up under Linux. These machines don't have
> ASUS_WMI_DEVID_CAMERA_LED, so asus-wmi never registers asus::camera. The
> firmware exposes the state through ASUS_WMI_DEVID_CAMERA_LED_NEG instead.
> 
> Reading CAMERA_LED_NEG is what drives the LED: the DSTS handler reads the
> camera state from the EC and writes it to the LED GPIO before returning
> it. The set side can't be used, the firmware only accepts DEVS on this
> device once per boot.
> 
> So read it at probe, which fixes the LED being dark after a cold boot
> with the camera disabled, and after every camera key event. Also
> register a read-only asus::camera LED on these machines so userspace can
> see the camera state and gets a brightness_hw_changed event on each key
> press.
> 
> This builds on José Guilherme de Castro Rodrigues' v2, which added the
> read after the camera key event.

You should retain his Signed-off-by tag if that's the case + add 
Co-developed-by tag.

> Link: https://lore.kernel.org/r/adg6GzkykThAB_4u@djouze-zen
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221752
> Assisted-by: Claude:claude-opus-5-5 iasl
> Signed-off-by: Zane <git@xxxxxxxxxxxx>

Please see what is required when you're signing off something:

Documentation/process/submitting-patches.rst

Also, you need to use your real name, not some nickname (basically what 
you'd use to sign a paper document/contract/etc.

> ---
> José, this is a respin of your v2 since it had stalled, I hope that's ok.
> Happy to drop it if you'd rather send v3 yourself, or to add your
> Co-developed-by/Signed-off-by if you want them on it.
> 
> Changes in v3:
> - Rebased on pdx86 for-next
> - Also read CAMERA_LED_NEG at probe, so the LED is right after a cold boot
> - Register a read-only asus::camera LED when only CAMERA_LED_NEG exists,
>   with brightness_hw_changed on key presses (Ilpo's suggestion on v2)
> - Comment on why the read is what updates the LED (also from v2 review)
> 
> Tested on a Zenbook S 14 UX5406SA, BIOS 309, on the Fedora 7.2.9 kernel
> with the same change applied to its asus-wmi:
> - Key presses: the LED, asus::camera and the camera output (live picture
>   vs. the firmware's grey "camera disabled" frame) switch together every
>   time, and brightness_hw_changed follows.
> - Cold boot with the camera disabled: the LED is lit and asus::camera
>   reads 1 before anything is pressed. Without the patch the LED stays dark
>   until the next key press.
> - Suspend/resume: the LEDs come back correctly, but that's the firmware
>   restoring them, it does the same without the patch. So nothing is done
>   on resume.
> 
> A Zenbook S 16 UM5606WA owner reported on the bug that reading
> CAMERA_LED_NEG after the key event (WMI code 0x85 there) fixes it on that
> machine too. The DSDT details are in the bugzilla entry.
> 
> I used Claude (Anthropic's AI assistant) while working on this. It helped
> me read through the DSDT, drafted the changes on top of v2 and wrote the
> test scripts. I went through the patch myself and ran the tests on my
> laptop.
> 
> v2: https://lore.kernel.org/r/adg6GzkykThAB_4u@djouze-zen
> ---
>  drivers/platform/x86/asus-wmi.c            | 72 ++++++++++++++++++++++++++++++
>  include/linux/platform_data/x86/asus-wmi.h |  2 +-
>  2 files changed, 73 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index fb1d4a0..fd2ba8c 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -72,6 +72,8 @@ module_param(fnlock_default, bool, 0444);
>  #define NOTIFY_KBD_TTP			0xae
>  #define NOTIFY_LID_FLIP			0xfa
>  #define NOTIFY_LID_FLIP_ROG		0xbd
> +#define NOTIFY_CAMERA_TOGGLE_1		0x82
> +#define NOTIFY_CAMERA_TOGGLE_2		0x85
>  #define NOTIFY_KEYSTONE			0xb4
>  
>  #define ASUS_WMI_FNLOCK_BIOS_DISABLED	BIT(0)
> @@ -312,6 +314,7 @@ struct asus_wmi {
>  	u32 kbd_rgb_dev;
>  	bool kbd_rgb_state_available;
>  	bool oobe_state_available;
> +	bool camera_neg_led_available;
>  
>  	u8 throttle_thermal_policy_mode;
>  	u32 throttle_thermal_policy_dev;
> @@ -2096,6 +2099,53 @@ static int camera_led_set(struct led_classdev *led_cdev,
>  	return err < 0 ? err : 0;
>  }
>  
> +static bool is_camera_toggle(int code)
> +{
> +	return code == NOTIFY_CAMERA_TOGGLE_1 || code == NOTIFY_CAMERA_TOGGLE_2;
> +}
> +
> +/*
> + * Some models (e.g. Zenbook S 14 UX5406SA, Zenbook S 16 UM5606WA) have no
> + * ASUS_WMI_DEVID_CAMERA_LED. The firmware handles the camera key itself and
> + * only exposes the state through ASUS_WMI_DEVID_CAMERA_LED_NEG, and reading
> + * that has a side effect: the firmware copies the state to the LED GPIO.
> + * Nothing else updates the LED, so read it at probe and after every camera
> + * key event. Setting it is no use, the firmware accepts DEVS on this device
> + * only once per boot.
> + *
> + * Returns 1 if the camera is disabled (LED lit), 0 if enabled, or -errno.
> + */
> +static int camera_neg_led_sync(struct asus_wmi *asus)
> +{
> +	u32 result;
> +	int err;
> +
> +	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_CAMERA_LED_NEG, &result);
> +	if (err)
> +		return err;
> +
> +	return !(result & ASUS_WMI_DSTS_STATUS_BIT);
> +}
> +
> +static enum led_brightness camera_neg_led_get(struct led_classdev *led_cdev)
> +{
> +	struct asus_wmi *asus = container_of(led_cdev, struct asus_wmi, camera_led);

Missing include (pre-existing problem but lets finally fix it).

> +	int state = camera_neg_led_sync(asus);
> +
> +	return state < 0 ? LED_OFF : state;
> +}
> +
> +/* The firmware owns this LED; a write just resyncs it with the camera state. */
> +static int camera_neg_led_set(struct led_classdev *led_cdev,
> +			      enum led_brightness brightness)
> +{
> +	struct asus_wmi *asus = container_of(led_cdev, struct asus_wmi, camera_led);
> +
> +	if (!(led_cdev->flags & LED_UNREGISTERING))
> +		camera_neg_led_sync(asus);
> +	return 0;
> +}
> +
>  static void asus_wmi_led_exit(struct asus_wmi *asus)
>  {
>  	scoped_guard(spinlock_irqsave, &asus_ref.lock)
> @@ -2233,6 +2283,17 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
>  		asus->camera_led.brightness_get = camera_led_get;
>  		asus->camera_led.brightness_set_blocking = camera_led_set;
>  
> +		rv = led_classdev_register(&asus->platform_device->dev,
> +						&asus->camera_led);
> +		if (rv)
> +			goto error;
> +	} else if (asus->camera_neg_led_available) {
> +		asus->camera_led.name = "asus::camera";
> +		asus->camera_led.max_brightness = 1;
> +		asus->camera_led.flags = LED_BRIGHT_HW_CHANGED;
> +		asus->camera_led.brightness_get = camera_neg_led_get;
> +		asus->camera_led.brightness_set_blocking = camera_neg_led_set;
> +
>  		rv = led_classdev_register(&asus->platform_device->dev,
>  						&asus->camera_led);

This duplicates code so you should mostly reuse the existing block, and 
only branch where you really need something different (the handlers + 
flags).

>  		if (rv)
> @@ -4733,6 +4794,13 @@ static void asus_wmi_handle_event_code(int code, struct asus_wmi *asus)
>  	if (is_display_toggle(code) && asus->driver->quirks->no_display_toggle)
>  		return;
>  
> +	if (is_camera_toggle(code) && asus->camera_neg_led_available) {
> +		int state = camera_neg_led_sync(asus);
> +
> +		if (state >= 0 && (asus->camera_led.flags & LED_BRIGHT_HW_CHANGED))

And why is the second condition necessary??

> +			led_classdev_notify_brightness_hw_changed(&asus->camera_led, state);
> +	}
> +
>  	if (!sparse_keymap_report_event(asus->inputdev, code,
>  					key_value, autorelease))
>  		pr_info("Unknown key code 0x%x\n", code);
> @@ -5210,6 +5278,10 @@ static int asus_wmi_add(struct platform_device *pdev)
>  #endif /* IS_ENABLED(CONFIG_ASUS_WMI_DEPRECATED_ATTRS) */
>  
>  	asus->oobe_state_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_OOBE);
> +	asus->camera_neg_led_available =
> +		asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CAMERA_LED_NEG);
> +	if (asus->camera_neg_led_available)
> +		camera_neg_led_sync(asus);
>  
>  	if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_THROTTLE_THERMAL_POLICY))
>  		asus->throttle_thermal_policy_dev = ASUS_WMI_DEVID_THROTTLE_THERMAL_POLICY;
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 4ea1ccc..5964063 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -57,7 +57,7 @@
>  #define ASUS_WMI_DEVID_MUTE_LED	0x0004001C
>  
>  /* Disable Camera LED */
> -#define ASUS_WMI_DEVID_CAMERA_LED_NEG	0x00060078 /* 0 = on (unused) */
> +#define ASUS_WMI_DEVID_CAMERA_LED_NEG	0x00060078 /* 0 = on */
>  #define ASUS_WMI_DEVID_CAMERA_LED	0x00060079 /* 1 = on */
>  
>  /* Backlight and Brightness */
> 
> ---
> base-commit: ea40f1e9f07aab937b9a217633be7a1f66260394
> change-id: 20261017-asus-wmi-camera-led-06a6e05f01e2
> 
> Best regards,
> --  
> Zane <git@xxxxxxxxxxxx>
> 
> 

-- 
 i.