Touch screen usage eventually results in X server unresponsive to keyboard input
Submitted by Ben Gamari
Assigned to Xorg Project Team
Created attachment 89592 Full Xorg.log
This appears to have similar root cause to #66720.
I use XMonad on a Dell Latitude E7440. After a few dozen events on the touchscreen I find that the keyboard will cease to respond. This is accompanied by errors in Xorg.0.log,
[ 9794.788] (EE) BUG: triggered 'if (ti->listeners.type != LISTENER_GRAB && ti->listeners.type != LISTENER_POINTER_GRAB)' [ 9794.789] (EE) BUG: ../../Xi/exevents.c:1044 in ActivateEarlyAccept() [ 9794.789] (EE) [ 9794.789] (EE) Backtrace: [ 9794.789] (EE) 0: /usr/bin/X (xorg_backtrace+0x3d) [0x7f68034634fd] [ 9794.789] (EE) 1: /usr/bin/X (0x7f68032c1000+0x132072) [0x7f68033f3072] [ 9794.790] (EE) 2: /usr/bin/X (0x7f68032c1000+0x1336bb) [0x7f68033f46bb] [ 9794.790] (EE) 3: /usr/bin/X (0x7f68032c1000+0x135e02) [0x7f68033f6e02] [ 9794.790] (EE) 4: /usr/bin/X (0x7f68032c1000+0x156f46) [0x7f6803417f46] [ 9794.791] (EE) 5: /usr/bin/X (mieqProcessDeviceEvent+0x1cd) [0x7f680344581d] [ 9794.791] (EE) 6: /usr/bin/X (mieqProcessInputEvents+0xf7) [0x7f6803445937] [ 9794.791] (EE) 7: /usr/bin/X (ProcessInputEvents+0x9) [0x7f6803352f79] [ 9794.791] (EE) 8: /usr/bin/X (0x7f68032c1000+0x54f12) [0x7f6803315f12] [ 9794.792] (EE) 9: /usr/bin/X (0x7inaf68032c1000+0x4472a) [0x7f680330572a] [ 9794.792] (EE) 10: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf5) [0x7f6800ffcde5] [ 9794.792] (EE) 11: /usr/bin/X (0x7f68032c1000+0x44a6f) [0x7f6803305a6f]
I originally observed this on Ubuntu Saucy's 1.14.3 xserver. To confirm this wasn't Ubuntu-specific I built a package from the 1.14.4 tag and found similar behavior. It seems that #66720 fixed at least one issue similar to this. I haven't carefully tested this but it may be that the bug is less likely to occur while using Unity instead of XMonad.
Attachment 89592, "Full Xorg.log":