ubuntu-x-swat team mailing list archive

[Daniel Manrique <daniel@xxxxxxxxxxxxxxxxxxxxxx>]

I have been tinkering with the drivers for this hardware and I believe
this bug should be moved to kernel, as per
https://wiki.ubuntu.com/DebuggingTouchpadDetection.

The Samsung QX410 uses an Elantech trackpad. The psmouse driver includes
support for some Elantech pads, but this particular one isn't recognized
because it returns a different result when queried via the "magic knock"
(function elantech_detect in elantech.c). This happens before the
force_elantech module parameter comes into effect (which forces use of
elantech when the firmware version is not recognized, but AFTER the
magic knock has returned the expected result).

I forced the elantech driver to continue initializing the pad despite
the unexpected reply to magic knock, and this is what I got (dmesg
output):

[ 9721.216300] elantech: unexpected magic knock result 0x3c, 0x03, 0x00.
[ 9721.250065] elantech: Elantech version query result 0x85, 0x1b, 0x00.
[ 9721.284321] elantech: assuming hardware version 2, firmware version 133.27.0
[ 9721.318037] elantech: Synaptics capabilities query result 0x19, 0x14, 0x0c.
[ 9721.578902] elantech: retrying ps2 command 0xe6 (2).
[ 9722.094936] elantech: retrying ps2 command 0xf8 (2).
[ 9722.797061] elantech: retrying ps2 command 0xf8 (1).

If the system is rebooted with the modified psmouse driver, the device
gets properly reported as a touchpad and all the relevant controls
appear in the mouse control panel. However since data received from the
pad is apparently not decoded properly by the psmouse driver (different
encoding schema maybe), nothing really works: there's no pointer
movement and the only thing that generates events (as read by evtest)
are the left and right buttons (and then, not consistently).

I'm attaching output from evtest (keep in mind I was sliding my finger
across the pad and clicking buttons, all that registers are the button
clicks) and from dmesg, showing loss of sync and subsequent reconnection
from the driver.

I hope this helps with this bug, I guess a lot of newer computers will
start using these newer Elantech pads and it'd be great to have support
out of the box.

** Attachment added: "dmesg.txt"
   https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/681904/+attachment/1771052/+files/dmesg.txt

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https://bugs.launchpad.net/bugs/681904

Title:
  Samsung QX410 trackpad not recognized