Hi We've noticed a quite bizarre touchpad behavior on one specific laptop model, namely Acer TravelMate B115-M: occasionally the touchpad gets really confused under normal usage and begins to emit events autonomously, i.e. without any object touching the surface, which results in a totally uncontrollable jumpy pointer. On some occasions, the end result is a completely unresponsive, stationary pointer. Disabling and enabling the touchpad via Fn+F7 (the touchpad toggle function) or suspend+resume resets the condition back to normal. The touchpad is handled by psmouse driver. Removing and re-adding psmouse module does not fix the issue. Reproducing the symptoms under normal usage is quite difficult, but fortunately we (or to be more precise, Petri Toivola) found out that sliding a moist paper (a cleaning wipe) on the touchpad to make a full circle triggers the exactly same behavior (to be really precise, it does not trigger when the surface gets moist, but when it dries up, around 1-2 seconds). We call it The Wet Circle of Death. Similar behavior can be observed also on Windows 7: https://www.youtube.com/watch?v=nDLIVuBmTOY To me it seems like the touchpad somehow recalibrates itself and becomes highly sensitive and begins to emits touch events even when there's no one touching it. The sensitiveness can be observed by looking at MT_ABS values: in normal conditions maximum values are around 120, but in confused state they are around 190. Now, I wonder if there's anything I can do to fix this "programmatically"? I ftraced during Fn+F7 and it seemed to make just several ACPI reads and writes, the driver was not involved, and on the other hand, quite obviously, no ACPI calls were involved when modprobing, which explains why modprobing did not fix issue. Are those ACPI spells something the driver could be expanded to make? Is there anything the driver could do more to make the touchpad reset "properly"? On `modprobe psmouse`, dmesg says: [87072.953080] psmouse serio2: synaptics: queried max coordinates: x [..5662], y [..4728] [87072.982742] psmouse serio2: synaptics: queried min coordinates: x [1322..], y [1190..] [87073.040285] psmouse serio2: synaptics: Touchpad model: 1, fw: 8.1, id: 0x1e2b1, caps: 0xd40123/0x840300/0x126800, board id: 2991, fw id: 1626681 [87073.077169] input: SynPS/2 Synaptics TouchPad as /devices/platform/i8042/serio2/input/input88 I've tested on different kernel versions, 4.2.5 and 4.0.6 (and also on Ubuntu 3.13.0-55.94-generic), all behave the same. -- Tuomas -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
