[Bug 2161834] [NEW] asus_wmi: Fn Lock state resets on reboot and cannot be observed from userspace

Public bug reported: Hardware and software --------------------- System: ASUSTeK COMPUTER INC. ZenBook UX325UA/UM325UA, revision 1.0 BIOS: UX325UA.306 (2025-02-19) Ubuntu: Ubuntu 26.04 LTS Kernel on which the issue was reproduced: 7.0.0-28-generic Ubuntu kernel source package: linux-source-7.0.0 7.0.0-28.28 Expected behavior ----------------- Linux should provide a supported way to read and restore the last physical Fn Lock state selected with Fn+Esc, so that userspace can persist that state across boots. Windows on this laptop remembers/restores the selected state. Original behavior with the stock Ubuntu kernel ---------------------------------------------- The stock asus_wmi driver does not expose its current Fn Lock state through a supported userspace interface. At module probe it unconditionally initializes its private fnlock_locked state from the read-only fnlock_default module parameter (true by default) and calls the ASUS WMI device setter. A physical Fn+Esc press changes the state for the running session, but the selected state cannot be learned and restored reliably across the next module probe or boot. The relevant firmware interface is ASUS WMI device 0x00100023. Physical Fn+Esc produces ASUS WMI notification 0x4e. asus_wmi handles and consumes that notification internally: it toggles its private fnlock_locked value and calls the firmware setter, then returns without reporting an input key. Captures from the "Asus WMI hotkeys" evdev device showed ordinary ASUS hotkeys but no Fn+Esc event. Consequently, a normal userspace key watcher cannot solve this. It cannot observe notification 0x4e through evdev, cannot read the driver's private state, and cannot explicitly set that state through a supported runtime interface. The read-only fnlock_default parameter can only choose a fixed probe-time value; it cannot implement "remember the last physical selection." Concise reproduction using the original stock driver ---------------------------------------------------- 1. Boot Ubuntu 26.04 with its stock 7.0.0-28-generic asus_wmi module and no fnlock_default override. 2. Note whether F1-F12 or the alternate media actions are active without Fn. 3. Press physical Fn+Esc and verify that the mode changes for the running session. 4. Monitor the "Asus WMI hotkeys" input device while pressing Fn+Esc; no corresponding evdev key event is produced. 5. Reboot. The driver again applies its fixed fnlock_default value at probe instead of restoring the state selected in step 3. Investigation and proof of concept ---------------------------------- The original problem was reproduced and investigated with the stock Ubuntu driver before any workaround was installed. A local DKMS proof of concept was then built from Ubuntu's matching asus_wmi source. It exposes the driver's current state, accepts explicit 0 or 1 writes, and notifies a userspace watcher after a successful physical Fn+Esc transition. A root-only service can thereby persist the resulting state and restore it later. Testing confirmed that the driver state can be exposed and managed safely without synthesizing key input or accessing undocumented hardware registers. The currently running system does contain that local out-of-tree DKMS replacement and its local persistence services. It will therefore be visible in the Apport data attached to this report. It is evidence and a proof of concept only; it is not a proposed Ubuntu packaging solution, and the original stock-kernel finding predates its installation. No EFI variables, Windows partitions, firmware/BIOS settings, DSDT overrides, or raw embedded-controller registers were changed during the investigation. ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: linux-image-7.0.0-28-generic 7.0.0-28.28 ProcVersionSignature: Ubuntu 7.0.0-28.28-generic 7.0.12 Uname: Linux 7.0.0-28-generic x86_64 ApportVersion: 2.34.1-0ubuntu0.1 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Sat Jul 25 21:32:58 2026 InstallationDate: Installed on 2024-12-18 (584 days ago) InstallationMedia: Ubuntu 24.04.1 LTS "Noble Numbat" - Release amd64 (20240827.1) MachineType: ASUSTeK COMPUTER INC. ZenBook UX325UA_UM325UA ProcFB: 0 amdgpudrmfb SourcePackage: linux UpgradeStatus: Upgraded to resolute on 2026-05-04 (82 days ago) dmi.bios.date: 02/19/2025 dmi.bios.release: 5.19 dmi.bios.vendor: American Megatrends International, LLC. dmi.bios.version: UX325UA.306 dmi.board.asset.tag: ATN12345678901234567 dmi.board.name: UX325UA dmi.board.vendor: ASUSTeK COMPUTER INC. dmi.board.version: 1.0 dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: ASUSTeK COMPUTER INC. dmi.chassis.version: 1.0 dmi.ec.firmware.release: 3.6 dmi.modalias: dmi:bvnAmericanMegatrendsInternational,LLC.:bvrUX325UA.306:bd02/19/2025:br5.19:efr3.6:svnASUSTeKCOMPUTERINC.:pnZenBookUX325UA_UM325UA:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnUX325UA:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:sku:pfaZenBook: dmi.product.family: ZenBook dmi.product.name: ZenBook UX325UA_UM325UA dmi.product.version: 1.0 dmi.sys.vendor: ASUSTeK COMPUTER INC. ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug resolute wayland-session -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2161834 Title: asus_wmi: Fn Lock state resets on reboot and cannot be observed from userspace Status in linux package in Ubuntu: New Bug description: Hardware and software --------------------- System: ASUSTeK COMPUTER INC. ZenBook UX325UA/UM325UA, revision 1.0 BIOS: UX325UA.306 (2025-02-19) Ubuntu: Ubuntu 26.04 LTS Kernel on which the issue was reproduced: 7.0.0-28-generic Ubuntu kernel source package: linux-source-7.0.0 7.0.0-28.28 Expected behavior ----------------- Linux should provide a supported way to read and restore the last physical Fn Lock state selected with Fn+Esc, so that userspace can persist that state across boots. Windows on this laptop remembers/restores the selected state. Original behavior with the stock Ubuntu kernel ---------------------------------------------- The stock asus_wmi driver does not expose its current Fn Lock state through a supported userspace interface. At module probe it unconditionally initializes its private fnlock_locked state from the read-only fnlock_default module parameter (true by default) and calls the ASUS WMI device setter. A physical Fn+Esc press changes the state for the running session, but the selected state cannot be learned and restored reliably across the next module probe or boot. The relevant firmware interface is ASUS WMI device 0x00100023. Physical Fn+Esc produces ASUS WMI notification 0x4e. asus_wmi handles and consumes that notification internally: it toggles its private fnlock_locked value and calls the firmware setter, then returns without reporting an input key. Captures from the "Asus WMI hotkeys" evdev device showed ordinary ASUS hotkeys but no Fn+Esc event. Consequently, a normal userspace key watcher cannot solve this. It cannot observe notification 0x4e through evdev, cannot read the driver's private state, and cannot explicitly set that state through a supported runtime interface. The read-only fnlock_default parameter can only choose a fixed probe-time value; it cannot implement "remember the last physical selection." Concise reproduction using the original stock driver ---------------------------------------------------- 1. Boot Ubuntu 26.04 with its stock 7.0.0-28-generic asus_wmi module and no fnlock_default override. 2. Note whether F1-F12 or the alternate media actions are active without Fn. 3. Press physical Fn+Esc and verify that the mode changes for the running session. 4. Monitor the "Asus WMI hotkeys" input device while pressing Fn+Esc; no corresponding evdev key event is produced. 5. Reboot. The driver again applies its fixed fnlock_default value at probe instead of restoring the state selected in step 3. Investigation and proof of concept ---------------------------------- The original problem was reproduced and investigated with the stock Ubuntu driver before any workaround was installed. A local DKMS proof of concept was then built from Ubuntu's matching asus_wmi source. It exposes the driver's current state, accepts explicit 0 or 1 writes, and notifies a userspace watcher after a successful physical Fn+Esc transition. A root-only service can thereby persist the resulting state and restore it later. Testing confirmed that the driver state can be exposed and managed safely without synthesizing key input or accessing undocumented hardware registers. The currently running system does contain that local out-of-tree DKMS replacement and its local persistence services. It will therefore be visible in the Apport data attached to this report. It is evidence and a proof of concept only; it is not a proposed Ubuntu packaging solution, and the original stock-kernel finding predates its installation. No EFI variables, Windows partitions, firmware/BIOS settings, DSDT overrides, or raw embedded-controller registers were changed during the investigation. ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: linux-image-7.0.0-28-generic 7.0.0-28.28 ProcVersionSignature: Ubuntu 7.0.0-28.28-generic 7.0.12 Uname: Linux 7.0.0-28-generic x86_64 ApportVersion: 2.34.1-0ubuntu0.1 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Sat Jul 25 21:32:58 2026 InstallationDate: Installed on 2024-12-18 (584 days ago) InstallationMedia: Ubuntu 24.04.1 LTS "Noble Numbat" - Release amd64 (20240827.1) MachineType: ASUSTeK COMPUTER INC. ZenBook UX325UA_UM325UA ProcFB: 0 amdgpudrmfb SourcePackage: linux UpgradeStatus: Upgraded to resolute on 2026-05-04 (82 days ago) dmi.bios.date: 02/19/2025 dmi.bios.release: 5.19 dmi.bios.vendor: American Megatrends International, LLC. dmi.bios.version: UX325UA.306 dmi.board.asset.tag: ATN12345678901234567 dmi.board.name: UX325UA dmi.board.vendor: ASUSTeK COMPUTER INC. dmi.board.version: 1.0 dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: ASUSTeK COMPUTER INC. dmi.chassis.version: 1.0 dmi.ec.firmware.release: 3.6 dmi.modalias: dmi:bvnAmericanMegatrendsInternational,LLC.:bvrUX325UA.306:bd02/19/2025:br5.19:efr3.6:svnASUSTeKCOMPUTERINC.:pnZenBookUX325UA_UM325UA:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnUX325UA:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:sku:pfaZenBook: dmi.product.family: ZenBook dmi.product.name: ZenBook UX325UA_UM325UA dmi.product.version: 1.0 dmi.sys.vendor: ASUSTeK COMPUTER INC. 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