the touchpad won't work after closing and opening the lid on some laptops

the touchpad won't work after closing and opening the lid on some laptops

[Hui Wang]

The problem:

On some lenovo laptops (this problem has been reproduced on 3 lenovo
laptop models), we let the machine boot into the desktop and login to
the desktop, the touchpad workes very well. But After we close the
lid then after a while open the lid, the touchpad won't work anymore.
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1089105



The root cause:

Through investigation, i found on some lenovo laptop models, when we
close the lid, the i8042/keyboard will generate a touchpad toggle key
event (generating a keycode same as the one generated by pressing
touchpad toggle functionkey/hotkey), while opening the lid, the
i8042/keyboard also generate a touchpad toggle key event.

If users close the lid under the gnome environment, the touchpad toggle
key event will be captured by the gnome-settings-daemon, so the touchpad
is disabled by the daemon, when users open the lid, the system will go to
the login window (gnome-screensaver), so the touchpad toggle key event
generated by opening lid doesn't pass to gnome-settings-daemon, so the
touchpad doesn't restore to the original status.

The keyboard driver is:
drivers/input/keyboard/atkbd.c



How to identify a machine whether has this problem or not:

An easy way to identify whether the machine has this problem is:
booting to gnome environment, pressing ALT+CTRL+F1 to enter text console,
executing showkey, closing lid, waiting several seconds, opening the lid,
if following logs are produced, your machine will have this problem.

keycode 191 press
keycode 191 release
keycode 191 press
keycode 191 release



My question:

Most of lenovo laptop models don't generate touchpad toggle event when
closing or opening the lid, so far this problem only happens on 3 laptop
models. I don't know who let the i8042/keyboard generate a touchpad toggle
key event when closing or opening the lid on those machines, do we have
a software/firmware method to let the i8042/keyboard don't generate this
event when closing or opening the lid?


Thanks,
Hui.