I think this bug is related with 53669: https://bugs.freedesktop.org/show_bug.cgi?id=53669 I open a new bug following the advice of Petter Hutteter https://bugs.freedesktop.org/show_bug.cgi?id=53669#c2
I have a wetab tablet with Arch 64 bits and xf86-input-evdev 2.7.3. I also use LXDE with openbox.
With the xf86-input-evdev from Arch's repo (mtdev is a dependence), changing 'Coordinate Transformation Matrix' property in my egalax touchscreen makes the cursor to 'rotate'. If I click on the screen then the cursor is moving at circles very fast. The tablet is completely unusable. I've read bugs 40169 and 50664, but I think my bug is different.
Taking on account bug 53669, I have built the evdev driver from Arch's PKGBUILD removing 'mtdev' as a dependence. Now 'Coordinate Transformation Matrix' property works fine, so I think that is a 'mtdev' dependent problem. Please note this bug is not Arch dependent or evdev version dependent, I suffered in the same hardware with Lubuntu 12.04 (I supposed ubuntu's xserver-xorg-input-driver 2.7.0 is bilt with mtdev support).
PD: using 'Evdev Axes Swap' and 'Evdev Axis Inversion' properties to rotate the touchscreen with the mtdev driver is not an option (bug 53669). The only way to sucesfully rotate my touchscreen is using a non-mtdev evdev driver. Unfortunately a new problem appears (bug 54353).
Please ask for any log or any additional information I can upload.
Bug is 2 years old, pretending it got fixed. Please re-open if this is still an issue.