https://bugs.kde.org/show_bug.cgi?id=525668
--- Comment #2 from roc <[email protected]> --- ## Additional technical evidence I would like to add the following low-level observations from an affected S3/resume cycle. ### Input device identity remains unchanged Before and after the failure, the ALPS device remains: AlpsPS/2 ALPS GlidePoint Kernel input device: /dev/input/event13 udev: /devices/platform/i8042/serio1/input/input9/event13 Relevant udev properties: ID_INPUT=1 ID_INPUT_TOUCHPAD=1 ID_BUS=i8042 ID_PATH=platform-i8042-serio-1 The device does not disappear or get re-enumerated during the failure. ### KWin device state While clicks are not working, querying KWin gives: name = AlpsPS/2 ALPS GlidePoint enabled = true Therefore the KWin input device is still present and enabled. ### libinput While the failure is active: sudo libinput debug-events --device /dev/input/event13 continues to emit normal POINTER_MOTION events. This means the input device continues producing motion events after resume. The failure is therefore not a complete loss of the device or pointer motion. ### Cross-device failure The most important observation is that the failure is not limited to the ALPS device. At the same time: * the internal ALPS touchpad can move the pointer but cannot click * an external USB mouse can move the pointer but cannot click Thus pointer-button functionality is lost across multiple pointer devices. ### Suspend/resume sequence The problem occurs after actual S3/deep suspend: PM: suspend entry (deep) ACPI: PM: Low-level resume complete PM: suspend exit PowerDevil also reports: PrepareForSleep(true=prepare) PrepareForSleep(false=resume) ### KWin/libinput warning At an affected resume, KWin reports: Libinput: event13 - AlpsPS/2 ALPS GlidePoint: client bug: event processing lagging behind by 3158ms, your system is too slow KWin simultaneously reported similar event-processing lag for the Power Button devices: event1 - Power Button: client bug: event processing lagging behind by 1610ms event3 - Power Button: client bug: event processing lagging behind by 1607ms ### Recovery behavior The KDE "Touchpad Toggle" action is sufficient to restore pointer clicking system-wide: 1. Touchpad Off 2. Touchpad On After this, both the internal touchpad and external USB mouse can click again. This is notable because toggling the touchpad restores clicking on a separate USB mouse as well. This suggests that the operation is affecting shared pointer/input state rather than simply restarting the ALPS device. ### psmouse test Reloading the ALPS/PS2 kernel driver: sudo modprobe -r psmouse && sudo modprobe psmouse does not provide a permanent solution. The problem can return after subsequent S3 resume or boot. ### Kernel comparison The issue has been observed on: linux-cachyos 7.2.4-3 and also on: linux-cachyos-lts 6.18.50-3 It is much more frequent on 7.2.4-3, but it is not completely absent on 6.18.50-3. ### Current interpretation The evidence currently points away from: * disappearance of the ALPS device * loss of the psmouse/i8042 device * KWin disabling the touchpad * complete libinput failure * an ALPS-only hardware problem The common failure is pointer-button handling/routing after S3 resume. The key distinction is: pointer motion continues + multiple pointer devices lose clicking + the devices remain present + KWin reports the ALPS device enabled=true + libinput continues receiving motion + KDE Touchpad Off → On restores clicking globally This makes KWin pointer-button state/event routing after resume a strong area for investigation, while leaving open the possibility of a lower-level interaction between resume, libinput and KWin. I am providing these observations to help narrow the fault domain and avoid treating this as a conventional "touchpad not detected" problem. -- You are receiving this mail because: You are watching all bug changes.
