Re: [PATCH v10 10/11] platform/x86: asus-wmi: add keyboard brightness event handler

Antheas Kapenekakis
2025-11-26T20:39:34Z

On Wed, 26 Nov 2025 at 21:23, Denis Benato <benato.denis96@gmail.com> wrote:
>
>
> On 11/22/25 12:00, Antheas Kapenekakis wrote:
> > The keyboard brightness control of Asus WMI keyboards is handled in
> > kernel, which leads to the shortcut going from brightness 0, to 1,
> > to 2, and 3.
> >
> > However, for HID keyboards it is exposed as a key and handled by the
> > user's desktop environment. For the toggle button, this means that
> > brightness control becomes on/off. In addition, in the absence of a
> > DE, the keyboard brightness does not work.
> >
> > Therefore, expose an event handler for the keyboard brightness control
> > which can then be used by hid-asus. Since this handler is called from
> > an interrupt context, defer the actual work to a workqueue.
> >
> > In the process, introduce ASUS_EV_MAX_BRIGHTNESS to hold the constant
> > for maximum brightness since it is shared between hid-asus/asus-wmi.
> >
> > Reviewed-by: Luke D. Jones <luke@ljones.dev>
> > Tested-by: Luke D. Jones <luke@ljones.dev>
> > Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
> > ---
> > drivers/platform/x86/asus-wmi.c | 46 +++++++++++++++++++---
> > include/linux/platform_data/x86/asus-wmi.h | 13 ++++++
> > 2 files changed, 54 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> > index 84cde34ab6a8..a69464e45ca4 100644
> > --- a/drivers/platform/x86/asus-wmi.c
> > +++ b/drivers/platform/x86/asus-wmi.c
> > @@ -1719,6 +1719,44 @@ static void kbd_led_update_all(struct work_struct *work)
> > }
> > }
> >
> > +/*
> > + * This function is called from hid-asus to inform asus-wmi of brightness
> > + * changes initiated by the keyboard backlight keys.
> > + */
> > +int asus_hid_event(enum asus_hid_event event)
> > +{
> > + struct asus_wmi *asus;
> > + int brightness;
> > +
> > + guard(spinlock_irqsave)(&asus_ref.lock);
> > + asus = asus_ref.asus;
> > + if (!asus || !asus->kbd_led_registered)
> > + return -EBUSY;
> > +
> > + brightness = asus->kbd_led_wk;
> > +
> > + switch (event) {
> > + case ASUS_EV_BRTUP:
> > + brightness += 1;
> > + break;
> > + case ASUS_EV_BRTDOWN:
> > + brightness -= 1;
> > + break;
> > + case ASUS_EV_BRTTOGGLE:
> > + if (brightness >= ASUS_EV_MAX_BRIGHTNESS)
> > + brightness = 0;
> > + else
> > + brightness += 1;
> > + break;
> > + }
> > +
> > + asus->kbd_led_wk = clamp_val(brightness, 0, ASUS_EV_MAX_BRIGHTNESS);
> > + asus->kbd_led_notify = true;
> > + queue_work(asus->led_workqueue, &asus->kbd_led_work);
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(asus_hid_event);
> > +
> > /*
> > * These functions actually update the LED's, and are called from a
> LEDs as opposed to LED's?

I agree with you, but the author of that line probably wouldn't -
depends on author dialect and both are usually correct.

When making acronyms plural, adding a ' is usually accepted as
correct. But this is not added as part of this series, so you can do a
reword commit if you wish

Antheas

> > * workqueue. By doing this as separate work rather than when the LED
> > @@ -1801,13 +1839,11 @@ static void do_kbd_led_set(struct led_classdev *led_cdev, int value)
> > {
> > struct asus_hid_listener *listener;
> > struct asus_wmi *asus;
> > - int max_level;
> >
> > asus = container_of(led_cdev, struct asus_wmi, kbd_led);
> > - max_level = asus->kbd_led.max_brightness;
> >
> > scoped_guard(spinlock_irqsave, &asus_ref.lock)
> > - asus->kbd_led_wk = clamp_val(value, 0, max_level);
> > + asus->kbd_led_wk = clamp_val(value, 0, ASUS_EV_MAX_BRIGHTNESS);
> >
> > if (asus->kbd_led_avail)
> > kbd_led_update(asus);
> > @@ -2011,7 +2047,7 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
> > asus->kbd_led.flags = LED_BRIGHT_HW_CHANGED;
> > asus->kbd_led.brightness_set = kbd_led_set;
> > asus->kbd_led.brightness_get = kbd_led_get;
> > - asus->kbd_led.max_brightness = 3;
> > + asus->kbd_led.max_brightness = ASUS_EV_MAX_BRIGHTNESS;
> > asus->kbd_led_avail = !kbd_led_read(asus, &led_val, NULL);
> > INIT_WORK(&asus->kbd_led_work, kbd_led_update_all);
> >
> > @@ -4530,7 +4566,7 @@ static void asus_wmi_handle_event_code(int code, struct asus_wmi *asus)
> > return;
> > }
> > if (code == NOTIFY_KBD_BRTTOGGLE) {
> > - if (led_value == asus->kbd_led.max_brightness)
> > + if (led_value == ASUS_EV_MAX_BRIGHTNESS)
> > kbd_led_set_by_kbd(asus, 0);
> > else
> > kbd_led_set_by_kbd(asus, led_value + 1);
> > diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> > index d347cffd05d5..7b872b5d0960 100644
> > --- a/include/linux/platform_data/x86/asus-wmi.h
> > +++ b/include/linux/platform_data/x86/asus-wmi.h
> > @@ -178,6 +178,14 @@ struct asus_hid_listener {
> > void (*brightness_set)(struct asus_hid_listener *listener, int brightness);
> > };
> >
> > +enum asus_hid_event {
> > + ASUS_EV_BRTUP,
> > + ASUS_EV_BRTDOWN,
> > + ASUS_EV_BRTTOGGLE,
> > +};
> > +
> > +#define ASUS_EV_MAX_BRIGHTNESS 3
> > +
> > #if IS_REACHABLE(CONFIG_ASUS_WMI)
> > void set_ally_mcu_hack(enum asus_ally_mcu_hack status);
> > void set_ally_mcu_powersave(bool enabled);
> > @@ -186,6 +194,7 @@ int asus_wmi_set_devstate(u32 dev_id, u32 ctrl_param, u32 *retval);
> > int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1, u32 *retval);
> > int asus_hid_register_listener(struct asus_hid_listener *cdev);
> > void asus_hid_unregister_listener(struct asus_hid_listener *cdev);
> > +int asus_hid_event(enum asus_hid_event event);
> > #else
> > static inline void set_ally_mcu_hack(enum asus_ally_mcu_hack status)
> > {
> > @@ -213,6 +222,10 @@ static inline int asus_hid_register_listener(struct asus_hid_listener *bdev)
> > static inline void asus_hid_unregister_listener(struct asus_hid_listener *bdev)
> > {
> > }
> > +static inline int asus_hid_event(enum asus_hid_event event)
> > +{
> > + return -ENODEV;
> > +}
> > #endif
> >
> > #endif /* __PLATFORM_DATA_X86_ASUS_WMI_H */
>