Dear kernel input developers,

While trying out 3.18-rc2, I noticed that the Elantech touchpad on my
laptop didn't work as intended anymore. Mouse movement and tapping one
finger worked, but scrolling and two finger tapping did not. X.org also
didn't recognise the touchpad as a synaptics touchpad anymore.

After googling around I found that i8042.nomux=0 brought it back to normal.

My laptop is a Clevo model W650SH with a keyboard and a touchpad attached,
and no touchschreen. Some output of dmesg is listed at the bottom, and the
result of dmidecode is attached.

Best regards,

Roel Aaij

Some dmesg output without i8042.nomux=0 (not fully functional touchpad)

[    1.221297] i8042: PNP: PS/2 Controller [PNP0303:PS2K,PNP0f13:ELNM] at 0x60,0x64 irq 1,12
[    1.226412] serio: i8042 KBD port at 0x60,0x64 irq 1
[    1.226414] serio: i8042 AUX port at 0x60,0x64 irq 12
[    1.229415] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input6
[    5.017142] psmouse serio1: elantech: assuming hardware version 3 (with firmware version 0x450f02)
[    5.018055] psmouse serio1: elantech: elantech_send_cmd query 0x02 failed.
[    5.018057] psmouse serio1: elantech: failed to query capabilities.
[    5.930158] input: PS/2 Elantech Touchpad as /devices/platform/i8042/serio1/input/input8


Some dmesg output with i8042.nomux=0 (fully functional touchpad)

[    1.361320] i8042: PNP: PS/2 Controller [PNP0303:PS2K,PNP0f13:ELNM] at 0x60,0x64 irq 1,12
[    1.366134] i8042: Detected active multiplexing controller, rev 1.1
[    1.367757] serio: i8042 KBD port at 0x60,0x64 irq 1
[    1.367759] serio: i8042 AUX0 port at 0x60,0x64 irq 12
[    1.367764] serio: i8042 AUX1 port at 0x60,0x64 irq 12
[    1.367765] serio: i8042 AUX2 port at 0x60,0x64 irq 12
[    1.367766] serio: i8042 AUX3 port at 0x60,0x64 irq 12
[    1.371243] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input6
[   99.389964] psmouse serio2: elantech: assuming hardware version 3 (with firmware version 0x450f02)
[   99.489797] psmouse serio2: elantech: Synaptics capabilities query result 0x79, 0x17, 0x0c.
[   99.819119] input: ETPS/2 Elantech Touchpad as /devices/platform/i8042/serio2/input/input22

P.S. The late timestamps in the last few lines are due to a "modprobe -r psmouse && modprobe psmouse"