Re: [PATCH v11] platform/x86: hp-wmi: Add multicolor LED support for HP keyboard backlight

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Tue, 15 Sep 2026, Ilpo Järvinen wrote:

> On Mon, 14 Sep 2026, Коненко Андрей Викторович wrote:
> 
> > Add support for the HP keyboard RGB backlight found on HP OMEN and
> > HP Victus laptops. These keyboards expose per-zone RGB control through
> > WMI commands.
> > 
> > Register multicolor LED class devices for each keyboard zone (up to 4
> > zones, depending on the keyboard type). Each zone exposes individual
> > red, green, and blue channels via the multicolor LED subsystem.
> > 
> > Also hardware-initiated brightness changes (e.g. via the keyboard
> > backlight hotkey, mostly fn+f4) are reported.
> > 
> > The color data is stored in a 128-byte color table managed by the
> > firmware, with RGB values starting at offset 25, packed sequentially
> > per zone.
> > 
> > Signed-off-by: Konenko Andrey Viktorovich <admin@aquinas.su>
> > 
> > ---
> > Changes since v10:
> >  - adapted for current linux-next (20260914)
> >  - Added Named Constants:
> > 	HP_BACKLIGHT_EVENT_ON — replaces magic number for backlight enable event
> > 	HP_BACKLIGHT_EVENT_OFF — replaces magic number for backlight disable event
> > 	HP_KBD_RGB_COLORS — replaces universally used literal 3 as RGB color/channel count
> >  - Refactored hp_kbd_brightness_set_by_hwd Function - Eliminated reliance on magic numbers in event handling logic (bugfix)
> >  - Event Filtering (critical bugfix):
> > 	Added event type filtering in hp_wmi_notify() before calling hp_kbd_brightness_set_by_hwd()
> > 	This prevents EC flooding and keyboard malfunction on some devices
> > 
> > Changes since v9:
> >  - Fixed corrupted long lines
> >  - Fixed changelog
> > 
> > Changes since v8:
> >  - No changes (It was mistake to resend email without any fix)
> > 
> > Changes since v7:
> >  - The LED class device names changed to be consistent with the documentation.
> > 
> > Changes since v6:
> >  - The LED class device names have been made more consistent with the 
> > documentation, in accordance with patch https://lore.kernel.org/linux-leds/
> > 20260504145434.12746-1-johannes.goede@oss.qualcomm.com/
> > underscores have been replaced with dashes where indicated.
> > 
> > Changes since v5:
> >  - LED class device names changed from a number to using a descriptive name 
> > for each zone.
> > 
> > v4: https://lore.kernel.org/all/20260303084022.7223-3-edip@medip.dev/
> > 
> > Changes since v4:
> >  - Fix circular dependencies
> > 
> > Changes since v3:
> >  - Merge the changes into a single commit
> > 
> > Changes since v1:
> >  - Fix mentioned style errors
> >  - Add Kconfig dependencies
> > 
> > ---
> >  drivers/platform/x86/hp/Kconfig  |   2 +
> >  drivers/platform/x86/hp/hp-wmi.c | 298 ++++++++++++++++++++++++++++++-
> >  2 files changed, 299 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/platform/x86/hp/Kconfig b/drivers/platform/x86/hp/Kconfig
> > index dd51491b9bcd..2a1841cbec76 100644
> > --- a/drivers/platform/x86/hp/Kconfig
> > +++ b/drivers/platform/x86/hp/Kconfig
> > @@ -45,6 +45,8 @@ config HP_WMI
> >  	select INPUT_SPARSEKMAP
> >  	select ACPI_PLATFORM_PROFILE
> >  	select HWMON
> > +	select LEDS_CLASS
> > +	select LEDS_CLASS_MULTICOLOR
> >  	help
> >  	  Say Y here if you want to support WMI-based hotkeys on HP laptops and
> >  	  to read data from WMI such as docking or ambient light sensor state.
> > diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
> > index 615b4cf6fc45..cf57b6b00b01 100644
> > --- a/drivers/platform/x86/hp/hp-wmi.c
> > +++ b/drivers/platform/x86/hp/hp-wmi.c
> > @@ -28,6 +28,8 @@
> >  #include <linux/kstrtox.h>
> >  #include <linux/limits.h>
> >  #include <linux/minmax.h>
> > +#include <linux/led-class-multicolor.h>
> > +#include <linux/leds.h>
> >  #include <linux/module.h>
> >  #include <linux/mutex.h>
> >  #include <linux/platform_device.h>
> > @@ -61,6 +63,10 @@ enum hp_ec_offsets {
> >  #define HP_FAN_SPEED_AUTOMATIC	 0x00
> >  #define HP_POWER_LIMIT_DEFAULT	 0x00
> >  #define HP_POWER_LIMIT_NO_CHANGE 0xFF
> > +#define HP_COLOR_TABLE_PADDING  25
> > +#define HP_BACKLIGHT_EVENT_ON   0x2
> > +#define HP_BACKLIGHT_EVENT_OFF  0x0
> > +#define HP_KBD_RGB_COLORS       3
> >  #define HPWMI_MUX_MODE_UMA		BIT(0)
> >  #define HPWMI_MUX_MODE_HYBRID		BIT(1)
> >  #define HPWMI_MUX_MODE_DISCRETE		BIT(2)
> > @@ -106,6 +112,14 @@ enum hp_thermal_profile {
> >  	HP_THERMAL_PROFILE_QUIET			= 0x03,
> >  };
> >  
> > +enum hp_keyboard_type {
> > +	HP_KEYBOARD_TYPE_NOBACKLIGHT		= 0x0,
> > +	HP_KEYBOARD_TYPE_FOURZONE_WITH_NUMPAD	= 0x1,
> > +	HP_KEYBOARD_TYPE_FOURZONE_WITHOUT_NUMPAD	= 0x2,
> > +	HP_KEYBOARD_TYPE_RGB_PER_KEY		= 0x3,
> > +	HP_KEYBOARD_TYPE_SINGLEZONE_WITH_NUMPAD	= 0x4,
> > +	HP_KEYBOARD_TYPE_SINGLEZONE_WITHOUT_NUMPAD	= 0x5,
> > +};
> >  
> >  struct thermal_profile_params {
> >  	u8 performance;
> > @@ -433,16 +447,27 @@ enum hp_wmi_gm_commandtype {
> >  	HPWMI_GET_GPU_THERMAL_MODES_QUERY	= 0x21,
> >  	HPWMI_SET_GPU_THERMAL_MODES_QUERY	= 0x22,
> >  	HPWMI_SET_POWER_LIMITS_QUERY		= 0x29,
> > +	HPWMI_GET_KEYBOARD_TYPE_QUERY		= 0x2b,
> >  	HPWMI_VICTUS_S_FAN_SPEED_GET_QUERY	= 0x2D,
> >  	HPWMI_VICTUS_S_FAN_SPEED_SET_QUERY	= 0x2E,
> >  	HPWMI_VICTUS_S_GET_FAN_TABLE_QUERY	= 0x2F,
> >  };
> >  
> > +enum hp_wmi_backlight_commandtype {
> > +	HPWMI_BACKLIGHT_COLOR_GET_QUERY		= 0x02,
> > +	HPWMI_BACKLIGHT_COLOR_SET_QUERY		= 0x03,
> > +	HPWMI_BACKLIGHT_BRIGHTNESS_GET_QUERY	= 0x04,
> > +	HPWMI_BACKLIGHT_BRIGHTNESS_SET_QUERY	= 0x05,
> > +	HPWMI_BACKLIGHT_SET_OFF_QUERY		= 0x64,
> > +	HPWMI_BACKLIGHT_SET_ON_QUERY		= 0xE4,
> > +};
> > +
> >  enum hp_wmi_command {
> >  	HPWMI_READ	= 0x01,
> >  	HPWMI_WRITE	= 0x02,
> >  	HPWMI_ODM	= 0x03,
> >  	HPWMI_GM	= 0x20008,
> > +	HPWMI_BACKLIGHT	= 0x20009,
> >  };
> >  
> >  enum hp_wmi_hardware_mask {
> > @@ -450,6 +475,24 @@ enum hp_wmi_hardware_mask {
> >  	HPWMI_TABLET_MASK	= 0x04,
> >  };
> >  
> > +struct hp_kbd_led_priv {
> > +	int zone;               /* Zone index (0-3) */
> > +	enum led_brightness last_brightness;  /* Brightness before turning off */
> > +};
> > +
> > +struct hp_mc_leds {
> > +	struct led_classdev_mc devices[4];
> > +	struct hp_kbd_led_priv priv[4];
> > +};
> > +
> > +/* zone naming for 4-zone keyboards (HP Omen) */
> > +static const char *const hp_zone_names_4[] = {
> > +	[0] = "zoned_backlight-right",
> > +	[1] = "zoned_backlight-center",
> > +	[2] = "zoned_backlight-left",
> > +	[3] = "zoned_backlight-wasd",
> > +};
> > +
> >  struct bios_return {
> >  	u32 sigpass;
> >  	u32 return_code;
> > @@ -530,6 +573,7 @@ static DEFINE_MUTEX(active_platform_profile_lock);
> >  static struct input_dev *hp_wmi_input_dev;
> >  static struct input_dev *camera_shutter_input_dev;
> >  static struct platform_device *hp_wmi_platform_dev;
> > +static struct hp_mc_leds hp_multicolor_leds;
> >  static struct device *platform_profile_device;
> >  static struct notifier_block platform_power_source_nb;
> >  static enum platform_profile_option active_platform_profile;
> > @@ -1338,6 +1382,8 @@ static struct attribute *hp_wmi_attrs[] = {
> >  };
> >  ATTRIBUTE_GROUPS(hp_wmi);
> >  
> > +static void hp_kbd_brightness_set_by_hwd(u32 event_data);
> > +
> >  static void hp_wmi_notify(union acpi_object *obj, void *context)
> >  {
> >  	u32 event_id, event_data;
> > @@ -1438,6 +1484,16 @@ static void hp_wmi_notify(union acpi_object *obj, void *context)
> >  	case HPWMI_PROXIMITY_SENSOR:
> >  		break;
> >  	case HPWMI_BACKLIT_KB_BRIGHTNESS:
> > +		/*
> > +		 * Only handle actual backlight events (0x0 and 0x2).
> > +		 * Other event_data values (like keyboard scan codes, e.g. 0x20 for 'd')
> > +		 * are keyboard events and should be handled via sparse_keymap,
> > +		 * not treated as brightness control commands.
> > +		 */
> > +		if (event_data != HP_BACKLIGHT_EVENT_ON &&
> > +		    event_data != HP_BACKLIGHT_EVENT_OFF)
> > +			break;
> > +		hp_kbd_brightness_set_by_hwd(event_data);
> >  		break;
> >  	case HPWMI_PEAKSHIFT_PERIOD:
> >  		break;
> > @@ -1700,6 +1756,244 @@ static int __init hp_wmi_rfkill2_setup(struct platform_device *device)
> >  	return err;
> >  }
> >  
> > +static struct hp_kbd_led_priv *hp_led_get_priv(struct led_classdev *led_cdev)
> > +{
> > +	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(led_cdev);
> > +	int zone = mc_cdev - hp_multicolor_leds.devices;
> > +
> > +	return &hp_multicolor_leds.priv[zone];
> > +}
> > +
> > +static int hp_kbd_backlight_set_rgb_color(int zone, int red, int green, int blue)
> > +{
> > +	u8 color_table[128];
> > +	int ret;
> > +
> > +	/*
> > +	 * Get the current color table and then change only the relevant parts.
> > +	 */
> > +	ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_COLOR_GET_QUERY,
> > +				  HPWMI_BACKLIGHT, color_table,
> > +				  zero_if_sup(color_table),
> > +				  sizeof(color_table));
> > +	if (ret)
> > +		return ret;
> > +
> > +	/*
> > +	 * RGB color data starts at offset 25 +3 per zone (r g b)
> > +	 * e.g. if zone 1 starts in 25 zone 2 starts in 28
> > +	 */
> > +	color_table[HP_COLOR_TABLE_PADDING + zone * HP_KBD_RGB_COLORS]     = red;
> > +	color_table[HP_COLOR_TABLE_PADDING + zone * HP_KBD_RGB_COLORS + 1] = green;
> > +	color_table[HP_COLOR_TABLE_PADDING + zone * HP_KBD_RGB_COLORS + 2] = blue;
> > +
> > +	ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_COLOR_SET_QUERY, HPWMI_BACKLIGHT,
> > +				  color_table, sizeof(color_table), sizeof(color_table));
> > +	if (ret < 0)
> > +		return ret;
> > +	if (ret)
> > +		return -EINVAL;
> > +
> > +	return 0;
> > +}
> > +
> > +static bool hp_kbd_backlight_is_on(void)
> > +{
> > +	u8 data;
> > +	int ret;
> > +
> > +	ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_BRIGHTNESS_GET_QUERY, HPWMI_BACKLIGHT, &data,
> > +				sizeof(data), sizeof(data));
> > +	if (ret)
> > +		return false;
> > +
> > +	return data == HPWMI_BACKLIGHT_SET_ON_QUERY;
> > +}
> > +
> > +static int hp_kbd_set_brightness(struct led_classdev *led_cdev,
> > +					enum led_brightness brightness)
> > +{
> > +	struct hp_kbd_led_priv *priv = hp_led_get_priv(led_cdev);
> > +	struct led_classdev_mc *mc_cdev;
> > +	struct led_classdev_mc *device;
> > +	int red, green, blue;
> > +	int ret;
> > +
> > +	if (!hp_kbd_backlight_is_on()) {
> > +		u8 data = HPWMI_BACKLIGHT_SET_ON_QUERY;
> > +
> > +		ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_BRIGHTNESS_SET_QUERY,
> > +					   HPWMI_BACKLIGHT, &data,
> > +					   sizeof(data), sizeof(data));
> > +		if (ret)
> > +			return ret;
> > +
> > +		/*
> > +		 * Turning the backlight on via WMI turns all zones,
> > +		 * so we need to restore the other zones' off state.
> > +		 */
> > +		for (int i = 0; i < ARRAY_SIZE(hp_multicolor_leds.devices); i++) {
> > +			if (i == priv->zone)
> > +				continue;
> > +
> > +			device = &hp_multicolor_leds.devices[i];
> > +			if (!device->led_cdev.name)
> > +				continue;
> > +			hp_kbd_backlight_set_rgb_color(i,
> > +				device->subled_info[0].brightness,
> > +				device->subled_info[1].brightness,
> > +				device->subled_info[2].brightness);
> > +		}
> > +	}
> > +
> > +	led_cdev->brightness = brightness;
> > +
> > +	mc_cdev = lcdev_to_mccdev(led_cdev);
> > +	led_mc_calc_color_components(mc_cdev, brightness);
> > +
> > +	red = mc_cdev->subled_info[0].brightness;
> > +	green = mc_cdev->subled_info[1].brightness;
> > +	blue = mc_cdev->subled_info[2].brightness;
> > +
> > +	return hp_kbd_backlight_set_rgb_color(priv->zone, red, green, blue);
> > +}
> > +
> > +static void hp_kbd_brightness_set_by_hwd(u32 event_data)
> > +{
> > +	struct device *dev = &hp_wmi_platform_dev->dev;
> > +	struct led_classdev *led_cdev;
> > +	struct hp_kbd_led_priv *priv;
> > +	u8 brightness;
> > +
> > +	for (int zone = 0; zone < ARRAY_SIZE(hp_multicolor_leds.devices); zone++) {
> > +		if (!hp_multicolor_leds.devices[zone].led_cdev.name)
> > +			continue;
> > +
> > +		led_cdev = &hp_multicolor_leds.devices[zone].led_cdev;
> > +		if (!led_cdev->dev)
> > +			continue;
> > +
> > +		priv = hp_led_get_priv(led_cdev);
> > +
> > +		switch (event_data) {
> > +		case HP_BACKLIGHT_EVENT_ON:
> > +			brightness = priv->last_brightness ? : LED_FULL;
> > +			break;
> > +		case HP_BACKLIGHT_EVENT_OFF:
> > +			priv->last_brightness = led_cdev->brightness;
> > +			brightness = LED_OFF;
> > +			break;
> > +		default:
> > +			dev_warn(dev, "Unknown keyboard backlight event - 0x%x\n",
> > +				 event_data);
> > +			return;
> > +		}
> > +
> > +		led_cdev->brightness = brightness;
> > +		led_classdev_notify_brightness_hw_changed(led_cdev, brightness);
> > +	}
> > +}
> > +
> > +static int __init hp_mc_leds_register(int num_zones)
> > +{
> > +	u8 color_table[128];
> > +	int ret;
> > +
> > +	ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_COLOR_GET_QUERY, HPWMI_BACKLIGHT,
> > +				  color_table, zero_if_sup(color_table),
> > +				  sizeof(color_table));
> > +	if (ret)
> > +		return ret;
> > +
> > +	for (int zone = 0; zone < num_zones; zone++) {
> > +		struct led_classdev_mc *multicolor_led_dev;
> > +		struct led_classdev *led_cdev;
> > +		struct mc_subled *mc_subled_info;
> > +		struct hp_kbd_led_priv *priv;
> > +		struct device *dev;
> > +
> > +		dev = &hp_wmi_platform_dev->dev;
> > +		multicolor_led_dev = &hp_multicolor_leds.devices[zone];
> > +		led_cdev = &multicolor_led_dev->led_cdev;
> > +		priv = &hp_multicolor_leds.priv[zone];
> > +
> > +		if (num_zones == 1)
> > +			led_cdev->name = devm_kasprintf(dev, GFP_KERNEL,
> > +				"hp::kbd_backlight");
> > +		else if (num_zones == 4 && zone < ARRAY_SIZE(hp_zone_names_4))
> > +			led_cdev->name = devm_kasprintf(dev, GFP_KERNEL,
> > +				"hp::kbd_%s",
> > +				hp_zone_names_4[zone]);
> > +		else if (num_zones > 1)
> > +			led_cdev->name = devm_kasprintf(dev, GFP_KERNEL,
> > +				"hp::kbd_zoned_backlight-%d",
> > +				zone);
> > +
> > +		if (!led_cdev->name)
> > +			return -ENOMEM;
> > +		led_cdev->brightness = hp_kbd_backlight_is_on() ?
> > +				       LED_FULL : LED_OFF;
> > +		led_cdev->max_brightness = LED_FULL;
> > +		led_cdev->brightness_set_blocking = hp_kbd_set_brightness;
> > +		led_cdev->flags = LED_CORE_SUSPENDRESUME |
> > +				  LED_RETAIN_AT_SHUTDOWN |
> > +				  LED_BRIGHT_HW_CHANGED;
> > +
> > +		mc_subled_info = devm_kzalloc(dev, sizeof(*mc_subled_info) * HP_KBD_RGB_COLORS,
> > +					      GFP_KERNEL);
> 
> Thanks for the update.
> 
> This looked very much devm_kcalloc() to me so I made that conversion 
> while applying.
> 
> PLEASE CHECK and yell loudly if you think I made an error while 
> converting it.
> 
> The patch is applied to the review-ilpo-next branch.

A time out. I've pulled this change from review-ilpo-next because of the 
reported config issue.

-- 
 i.