Mouse movement quality in Ubuntu

[Martin Olsson]

First make sure you have this package installed:
xserver-xorg-input-evdev

I think your kernel needs to have evdev support to, or at least an evdev 
module loaded (but my gutsy kernel just worked out of the box).

My original mouse configuration (which was really bad with all those 
latency problems) looked like this:

Section "InputDevice"
        Identifier      "Configured Mouse"
        Driver          "mouse"
        Option          "CorePointer"
        Option          "Device"                "/dev/input/mice"
        Option          "Protocol"              "ImPS/2"
        Option          "ZAxisMapping"          "4 5"
        Option          "Emulate3Buttons"       "true"
EndSection

The mouse configuration that I now use instead (the evdev one, which 
doesn't have any sweep-select latency problems at all) looks like this:

Section "InputDevice"
         Identifier      "Configured Mouse"
         Driver          "evdev"
         Option          "Device" "/dev/input/mice"
EndSection



To test this config out, sudo you favorite editor and comment out your 
old mouse config in /etc/X11/xorg.conf and use the evdev config above.

You don't need to reboot for the new settings to come into effect but 
you must unfortunately start X.org (this simplest way to do this is to 
press CTRL-ALT-BACKSPACE, I think this restarts gdm).

WARNING: While trying out different mouse configurations in xorg.conf I 
managed to screw up my xorg.conf file like at least 6 or 7 times. This 
meant that X.org could not start (not even the graphics would work for 
some weird reason). If you manage you nuke your installation like this, 
just choose "recovery mode" in GRUB which will boot you into a console 
based text interface. From here you can use nano/vi/joe etc to edit the 
xorg.conf file back into its original state (and then reboot).

PS. I have posted bug 144277 in launchpad suggesting that evdev becomes 
the default mouse driver in Ubuntu:
https://bugs.launchpad.net/ubuntu/+bug/144277



Martin


Francesco Fumanti wrote:
> Hello,
> 
> Thanks for this interesting piece of information.
> 
> Could you please paste the relevant section of the xorg.conf in a reply 
> to this email, to show what has to be changed? In fact, I tried to do 
> the change, but the X server did not startup correctly anymore. (I am 
> back to the previous settings)
> 
> Maybe I changed the wrong line in the xorg.conf file?
> 
> Cheers
> 
> Francesco
> 
> 
> 
> At 8:24 PM -0700 9/26/07, Martin Olsson wrote:
>> Hi,
>>
>> I always thought the mouse behaved a little weird in "Linux". When I
>> would drag-and-sweep select something with the mouse very quickly I
>> would often end up with a selection that was smaller than I intended.
>> Clearly there was some kind latency problem because X.org didn't get the
>> mouse down event until I had already moved the mouse cursor quit a bit.
>> I assume(d) that this was one of many unpolished things that would
>> eventually be corrected.
>>
>> Earlier this week a more experienced Linux user showed me a way to fix
>> this problem. Apparently, if I edit my xorg.conf file and switch the
>> mouse input driver to "evdev" the mouse becomes extremely snappy and
>> high precision. When I select stuff, exactly what I intended is
>> selected. I love it!
>>
>> This little revelation made me realize that there is probably many
>> people out there who are using Ubuntu with this kind of, not that
>> severe, but still annoying mouse latency problems. Fixing this might be
>> as simple as switching to "evdev" by default in Ubuntu (even though I
>> admit that I have no idea about the actual difference in scope/purpose
>> of the standard input driver versus the evdev driver).
>>
>>
>>
>>
>> Martin
>>
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