[PATCH v9 00/11] HID: asus: Fix ASUS ROG Laptop's Keyboard backlight handling

Antheas Kapenekakis
2025-11-20T09:46:30Z

This is a two part series which does the following:
- Clean-up init sequence
- Unify backlight handling to happen under asus-wmi so that all Aura
devices have synced brightness controls and the backlight button works
properly when it is on a USB laptop keyboard instead of one w/ WMI.

For more context, see cover letter of V1. Since V5, I removed some patches
to make this easier to merge.

---
V8: https://lore.kernel.org/all/20251101104712.8011-1-lkml@antheas.dev/
V7: https://lore.kernel.org/all/20251018101759.4089-1-lkml@antheas.dev/
V6: https://lore.kernel.org/all/20251013201535.6737-1-lkml@antheas.dev/
V5: https://lore.kernel.org/all/20250325184601.10990-1-lkml@antheas.dev/
V4: https://lore.kernel.org/lkml/20250324210151.6042-1-lkml@antheas.dev/
V3: https://lore.kernel.org/lkml/20250322102804.418000-1-lkml@antheas.dev/
V2: https://lore.kernel.org/all/20250320220924.5023-1-lkml@antheas.dev/
V1: https://lore.kernel.org/all/20250319191320.10092-1-lkml@antheas.dev/

Changes since V8:
- No functional changes
- Move legacy init patch to second, modify first patch so that their
diff is minimized
- Split "prevent binding to all HID devices on ROG" into two patches:
- moving backlight initialization into probe
- early exit to skip ->init check and rename
- Remove skipping vendor fixups for non-vendor devices. It is not possible
to read usages before the report fixups are applied, so it did not work
- In that patch, reword a comment to be single line and make is_vendor a bool
- Dismiss Luke's tags from "Add support for multiple kbd led handlers" as it
has drifted too far since he reviewed/tested it.

Changes since V7:
- Readd legacy init quirk for Dennis
- Remove HID_QUIRK_INPUT_PER_APP as a courtesy to asusctl
- Fix warning due to enum_backlight receiving negative values

Changes since V6:
- Split initialization refactor into three patches, update commit text
to be clearer in what it does
- Replace spinlock accesses with guard and scoped guard in all patches
- Add missing includes mentioned by Ilpo
- Reflow, tweak comment in prevent binding to all HID devices on ROG
- Replace asus_ref.asus with local reference in all patches
- Add missing kernel doc comments
- Other minor nits from Ilpo
- User reported warning due to scheduling work while holding a spinlock.
Restructure patch for multiple handlers to limit when spinlock is held to
variable access only. In parallel, setup a workqueue to handle registration
of led device and setting brightness. This is required as registering the
led device triggers kbd_led_get which needs to hold the spinlock to
protect the led_wk value. The workqueue is also required for the hid
event passthrough to avoid scheduling work while holding the spinlock.
Apply the workqueue to wmi brightness buttons as well, as that was
omitted before this series and WMI access was performed.
- On "HID: asus: prevent binding to all HID devices on ROG", rename
quirk HANDLE_GENERIC to SKIP_REPORT_FIXUP and only skip report fixup.
This allows other quirks to apply (applies quirk that fixes keyboard
being named as a pointer device).

Changes since V5:
- It's been a long time
- Remove addition of RGB as that had some comments I need to work on
- Remove folio patch (already merged)
- Remove legacy fix patch 11 from V4. There is a small chance that
without this patch, some old NKEY keyboards might not respond to
RGB commands according to Luke, but the kernel driver does not do
RGB currently. The 0x5d init is done by Armoury crate software in
Windows. If an issue is found, we can re-add it or just remove patches
1/2 before merging. However, init could use the cleanup.

Changes since V4:
- Fix KConfig (reported by kernel robot)
- Fix Ilpo's nits, if I missed anything lmk

Changes since V3:
- Add initializer for 0x5d for old NKEY keyboards until it is verified
that it is not needed for their media keys to function.
- Cover init in asus-wmi with spinlock as per Hans
- If asus-wmi registers WMI handler with brightness, init the brightness
in USB Asus keyboards, per Hans.
- Change hid handler name to asus-UNIQ:rgb:peripheral to match led class
- Fix oops when unregistering asus-wmi by moving unregister outside of
the spin lock (but after the asus reference is set to null)

Changes since V2:
- Check lazy init succeds in asus-wmi before setting register variable
- make explicit check in asus_hid_register_listener for listener existing
to avoid re-init
- rename asus_brt to asus_hid in most places and harmonize everything
- switch to a spinlock instead of a mutex to avoid kernel ooops
- fixup hid device quirks to avoid multiple RGB devices while still exposing
all input vendor devices. This includes moving rgb init to probe
instead of the input_configured callbacks.
- Remove fan key (during retest it appears to be 0xae that is already
supported by hid-asus)
- Never unregister asus::kbd_backlight while asus-wmi is active, as that
- removes fds from userspace and breaks backlight functionality. All
- current mainline drivers do not support backlight hotplugging, so most
userspace software (e.g., KDE, UPower) is built with that assumption.
For the Ally, since it disconnects its controller during sleep, this
caused the backlight slider to not work in KDE.

Changes since V1:
- Add basic RGB support on hid-asus, (Z13/Ally) tested in KDE/Z13
- Fix ifdef else having an invalid signature (reported by kernel robot)
- Restore input arguments to init and keyboard function so they can
be re-used for RGB controls.
- Remove Z13 delay (it did not work to fix the touchpad) and replace it
with a HID_GROUP_GENERIC quirk to allow hid-multitouch to load. Squash
keyboard rename into it.
- Unregister brightness listener before removing work queue to avoid
a race condition causing corruption
- Remove spurious mutex unlock in asus_brt_event
- Place mutex lock in kbd_led_set after LED_UNREGISTERING check to avoid
relocking the mutex and causing a deadlock when unregistering leds
- Add extra check during unregistering to avoid calling unregister when
no led device is registered.
- Temporarily HID_QUIRK_INPUT_PER_APP from the ROG endpoint as it causes
the driver to create 4 RGB handlers per device. I also suspect some
extra events sneak through (KDE had the @@@@@@).

Antheas Kapenekakis (11):
HID: asus: simplify RGB init sequence
HID: asus: initialize additional endpoints only for legacy devices
HID: asus: use same report_id in response
HID: asus: fortify keyboard handshake
HID: asus: move vendor initialization to probe
HID: asus: early return for ROG devices
platform/x86: asus-wmi: Add support for multiple kbd led handlers
HID: asus: listen to the asus-wmi brightness device instead of
creating one
platform/x86: asus-wmi: remove unused keyboard backlight quirk
platform/x86: asus-wmi: add keyboard brightness event handler
HID: asus: add support for the asus-wmi brightness handler

drivers/hid/hid-asus.c | 206 ++++++++++----------
drivers/platform/x86/asus-wmi.c | 214 ++++++++++++++++++---
include/linux/platform_data/x86/asus-wmi.h | 70 +++----
3 files changed, 318 insertions(+), 172 deletions(-)

base-commit: 6a23ae0a96a600d1d12557add110e0bb6e32730c
--
2.52.0