Hi Tuomas, It looks like some other people have reported similar issues with this particular touchpad module. I think there might be a hardware issue with some touchpads with the board/product id of 2991. Since this maybe a hardware issue there might not be a fix, but there might be a work around. This touchpad has a HID/I2C interface in addition to the PS/2 interface. You should see a line in dmesg which looks something like this: hid-multitouch 0018:06CB:2991.0001: input,hidraw0: <UNKNOWN> HID v1.00 Mouse [SYN1B7F:00 06CB:2991] on If you download and build rmihidtool (https://github.com/aduggan/rmi4utils), you can manually reset the touchpad and hopefully return it to a working state. The Fn+F7 on Windows is probably doing something similar by either cutting power to the touchpad or forcing a reset. Running this command will reset the touchpad: $ sudo rmihidtool -e /dev/hidraw0 If the touchpad stops working completely then you may need to rebind the driver so that the touchpad is put back into PTP mode: $ sudo rmihidtool -b /dev/hidraw0 On Mon, Nov 23, 2015 at 1:43 AM, Tuomas Räsänen <tuomasjjrasanen@xxxxxxxxxx> wrote: > 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. > Do you mean EV_ABS? I'm not quite sure which values would have a normal max of around 120. Generally, these types of situations where false contacts are being reported are hard to distinguish in the firmware or driver from real contacts. Even if you notice a specific pattern on your particular system it might manifest itself differently on other systems. Andrew > 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 -- 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
