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[Mikiausch <726832@xxxxxxxxxxxxxxxxxx>]

I don't know If this is caused by the same issue, but the problem is
quite siilar, so I attach this as a commen instead of filing a new bug.
I'm using debian testing / x.org 1.17.2 with a Lenovo U41 which has an
ALPS touchpad.

The problem is that the touchpad is way faster on the horizontal axis
than on the vertical axis: while a swipe from left to right will move
the pointer approximately from the left to the right screen edge, a
complete top-down swipe only covers one quarter of the screen - of
course influenced by the acceleration settings.

Fiddling with the "VertResolution" and "HorizResolution" options didn't
show any effect for me.

Looking at the code it seems that these options were actually rendered
useless when the synaptics driver scaling was removed in commit
#0fb59b3487d57523a03f078a2061e2ea0cacbc7c. The driver always passes the
resolution values reported by the device to the server instead of the
overwritten ones from the config.

Some debugging later, this is what the device reports to the server: 
minx: 0, maxx: 4095, resx: 40
miny: 0, maxy: 2047, resy: 71

So it looks like the device has indeed a different resolution in x and y
and this seems to get mix up the scaling somehow.


I tried to make the driver pass the VertResolution and HorizResolution parameters instead of the device values by changing some lines from synaptics.c:

xf86InitValuatorAxisStruct(dev, 0, axes_labels[0], min, max, priv->resx
* 1000, 0, priv->resx * 1000, Relative);

into

xf86InitValuatorAxisStruct(dev, 0, axes_labels[0], min, max,
priv->synpara.resolution_horiz * 1000, 0, priv->synpara.resolution_horiz
* 1000, Relative);

and

xf86InitValuatorAxisStruct(dev, 1, axes_labels[1], min, max, priv->resy
* 1000, 0, priv->resy * 1000, Relative);

into

xf86InitValuatorAxisStruct(dev, 1, axes_labels[1], min, max,
priv->synpara.resolution_vert * 1000, 0, priv->synpara.resolution_vert *
1000, Relative);


After that, setting both "VertResolution" and "HorizResolution" to the same value, makes the touchpad behave as expected. 

But I think the real problem is somewhere deeper in getevents.c

As far as I understand the scale_for_device_resolution function tries to
map the touch pad size to the screen size which works fine as long as
resolution_ratio equals 1 which is the case for all pads with an equal
x/y resolution and breaks on devices with uneven resolutions. But why is
the resolution involved in the scaling anyway? If we try to map 1the
device size to the screen size we don't need to bother about the device
resolution. The axis sizes and the screen resolution should be enough?!

-- 
You received this bug notification because you are a member of Desktop
Packages, which is subscribed to xserver-xorg-input-synaptics in Ubuntu.
https://bugs.launchpad.net/bugs/726832

Title:
  Touchpad speed scales with multimonitor size per axis

Status in XOrg-Driver-Synaptics:
  Confirmed
Status in xserver-xorg-input-synaptics package in Ubuntu:
  Incomplete

Bug description:
  When enabling a second screen, say horizontally next to the primary
  screen, horizontal touchpad speed increases proportionally to the
  increase in horizontal resolution. I assume the same happens when
  enabling multiple screens in a vertical configuration. So, it seems
  that touchpad speed is relative to the total screen layout size in
  each axis. This is quite irritating. It would be more reasonable to
  define speed in absolute terms (pixels/sec) rather than relative terms
  (% x/y resolution / sec), thereby keeping speed in both axes constant,
  regardless of the addition/removal of extra screens.

  I've noticed this on my Thinkpad W510 running Maverick amd64, the
  latest nvidia binary blob, utouch 1.1, synaptics-dkms 1.0.0, and
  xserver-xorg-input-synaptics 1.2.2-2ubuntu5

  Note that external mice don't exhibit this problem. This might be why
  this situation isn't encountered often: when plugged into an external
  monitor, the user is more likely to also plug in an external mouse
  rather than rely on the touchpad.

  This was brought up by Ricardo Caldeira at https://bugs.launchpad.net
  /xorg-driver-synaptics/+bug/308191/comments/187, and Duncan McGreggor
  replied at https://bugs.launchpad.net/xorg-driver-
  synaptics/+bug/308191/comments/189.

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