Comment 174 for bug 565543

The situation is the same or even worse for my laptop (a Dell Latitude E6420) in the latest upstream kernel. I tested with the plain 3.0 kernel from kernel.org (from source) and the ubuntu mainline kernel at http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.0-oneiric/ (both 64bit).

In the 2.6.38 kernel, the touchpad is recognized as "ImPS/2 ALPS GlidePoint", vertical scrolling works but settings like tapping cannot be configured.
In both new kernels my touchpad is recognized as a "PS/2 Generic Mouse" which is worse than in the default 2.6.38 kernel, because now even the vertical scrolling does not work anymore.

lennart@latitude ~ $ uname -a
Linux latitude 3.0.0-0300-generic #201107220917 SMP Fri Jul 22 09:20:45 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

lennart@latitude ~ $ cat /proc/bus/input/devices

[..]

I: Bus=0011 Vendor=0002 Product=0001 Version=0000
N: Name="PS/2 Generic Mouse"
P: Phys=isa0060/serio1/input0
S: Sysfs=/devices/platform/i8042/serio1/input/input8
U: Uniq=
H: Handlers=mouse0 event8
B: PROP=0
B: EV=7
B: KEY=70000 0 0 0 0
B: REL=3

I did some more research. I noticed some remarkable differences between the alps.c drivers in the 2.6 and 3.0 kernels. There are all kinds of functions missing in the 3.0 version, and I am not a kernel developer but it looks to me those missing functions are connected to the fact the ALPS is recognized as a PS/2 mouse in the newer kernel.

See attached file for the output to "diff linux-source-2.6.38/drivers/input/mouse/alps.c linux-3.0/drivers/input/mouse/alps.c"

Please let me know if you need more data.