Red Hat Bugzilla – Bug 584927
Problems with cursor movement when Xinerama layout is out of order
Last modified: 2010-11-15 13:24:50 EST
Description of problem:
If a Xinerama layout is created where a higher numbered display is placed anywhere besides to the right of a lower numbered display (in other words, to the left of, above, or below) then trying to move the cursor from the lower numbered display to the higher numbered display with out of order placement will cause the cursor position to be incorrectly displayed.
Version-Release number of selected component (if applicable):
Any Xinerama layout with out of order positioning should reproduce this problem.
Steps to Reproduce:
1. Create a Xinerama layout with two screens. Position screen 0 on the right and screen 1 on the left.
2. Move the cursor from screen 0 to screen 1.
3. Observe cursor movement as the cursor crosses over.
Once the cursor crosses over to screen 1, it will rapidly oscillate over a range of positions. The size of this range depends on cursor velocity when it crossed over. You should be able to move the cursor back to screen 0.
The cursor should move normally between screens, the same way it does if screen 0 is on the left and screen 1 is on the right.
This is a known regression in upstream X.org, but if RHEL6 is to ship with this regression, it will negatively impact a huge number of customers using Xinerama. See freedesktop.org bug below:
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux major release. Product Management has requested further
review of this request by Red Hat Engineering, for potential inclusion in a Red
Hat Enterprise Linux Major release. This request is not yet committed for
This bug must also apply to Fedora 12. Having my second monitor "leftof" of primary monitor in F11 worked fine. After upgrading to F12 via preupgrade my mouse will no longer travel to the second monitor with Xinerama enabled. If I disable Xinerama in xorg.conf the mouse will then travel to the second monitor.
I am looking for a clone of this bug opened against Fedora 12. If I cannot find one that applies I will clone this bug to create a new report.
This would appear to be the same issue noted in the now two-month old bug 567835 filed against F12. Props to Kevin for making the link.
Since the issue often (on my F12 system at least) leads to an unusable X session should it qualify for a higher priority than "low"?
The simple workaround to have dual monitors, F12 & an nvidia card is to change secondary monitors position in your server layout directive to "RightOf" (mine was using LeftOf). Do this and everything will work fine for a simple dual monitor setup.
The only thing left is the SIGTERM you now get in F12 when the xorg-nvidia driver is loaded.
@ comment #5 yes, that does work for a simple dual-monitor setup, but it is just a workaround as you said. It means you end up with your fullscreen OpenGL, login box and other 'default screen' stuff happening on the display you didn't want it on which can be an issue if the displays are different sizes or otherwise awkward to use in that configuration.
I've been putting up with my left screen being rightOf my right screen for months now just so I could keep my gaming on the centre screen. It's wonderfully mind-bending to have to keep pushing the pointer to the right as you turn your head to the left, then wondering why you can't escape the left monitor until you realise you need to move "more left" :-)
As far as I know there is no way currently to repair this behaviour with config tweaks, having a display left of the primary display is simply broken.
(sorry for duplicate reply to duplicate comment, but unsure if these two bugs would end up being merged and therefore where the discussion should be).
Looks backportable from master, devel ack.
This problem exists in Fedora 13 as well, despite xorg being updated to 1.8.0. The "fixed" xorg release is apparently 22.214.171.1241. The original poster has a link to the upstream bug and ultimate fix. It would be nice to see this fixed as moving the pointer off the right edge of my screen to get to my upper monitor is a bit counter-intuitive.. :)
it seems to be fixed as no strange movements are present and moving from one screen to another works in top/down, left/right and corner-connected positions
Red Hat Enterprise Linux 6.0 is now available and should resolve
the problem described in this bug report. This report is therefore being closed
with a resolution of CURRENTRELEASE. You may reopen this bug report if the
solution does not work for you.