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

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

[Zane via B4 Relay]

From: Zane <git@turtledev.nz>

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.

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@turtledev.nz>
---
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);
+	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);
 		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))
+			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@turtledev.nz>

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

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 9359 bytes --]

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

> From: Zane <git@turtledev.nz>
> 
> 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@turtledev.nz>

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@turtledev.nz>
> 
> 

-- 
 i.