This is what Xorg reports on its log, things look pretty messed up: [ 34.382] [mi] EQ overflowing. Additional events will be discarded until existing events are processed. [ 34.383] [ 34.383] Backtrace: [ 34.399] 0: /usr/bin/Xorg (xorg_backtrace+0x36) [0x7fc363f0ad16] [ 34.399] 1: /usr/bin/Xorg (mieqEnqueue+0x26b) [0x7fc363eebfbb] [ 34.399] 2: /usr/bin/Xorg (0x7fc363d8c000+0x66902) [0x7fc363df2902] [ 34.399] 3: /usr/lib/xorg/modules/input/evdev_drv.so (0x7fc35d818000+0x55d8) [0x7fc35d81d5d8] [ 34.399] 4: /usr/bin/Xorg (0x7fc363d8c000+0x8d947) [0x7fc363e19947] [ 34.399] 5: /usr/bin/Xorg (0x7fc363d8c000+0xb1c18) [0x7fc363e3dc18] [ 34.399] 6: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7fc3630b4000+0xf030) [0x7fc3630c3030] [ 34.399] 7: /lib/x86_64-linux-gnu/libc.so.6 (ioctl+0x7) [0x7fc361e90137] [ 34.399] 8: /usr/lib/x86_64-linux-gnu/libdrm.so.2 (drmIoctl+0x28) [0x7fc360204d08] [ 34.399] 9: /usr/lib/x86_64-linux-gnu/libdrm.so.2 (drmCommandWriteRead+0x1c) [0x7fc36020713c] [ 34.399] 10: /usr/lib/x86_64-linux-gnu/libdrm_radeon.so.1 (0x7fc35f8dd000+0x2309) [0x7fc35f8df309] [ 34.399] 11: /usr/lib/x86_64-linux-gnu/libdrm_radeon.so.1 (0x7fc35f8dd000+0x2534) [0x7fc35f8df534] [ 34.399] 12: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7fc35fae8000+0xbeacb) [0x7fc35fba6acb] [ 34.399] 13: /usr/lib/xorg/modules/libexa.so (0x7fc35f0b6000+0x5c0b) [0x7fc35f0bbc0b] [ 34.399] 14: /usr/lib/xorg/modules/libexa.so (0x7fc35f0b6000+0x81fa) [0x7fc35f0be1fa] [ 34.400] 15: /usr/lib/xorg/modules/libexa.so (0x7fc35f0b6000+0x51b1) [0x7fc35f0bb1b1] [ 34.400] 16: /usr/bin/Xorg (0x7fc363d8c000+0xd6f2f) [0x7fc363e62f2f] [ 34.400] 17: /usr/bin/Xorg (ChangeWindowAttributes+0x279) [0x7fc363e0aa79] [ 34.400] 18: /usr/bin/Xorg (0x7fc363d8c000+0x4d3fd) [0x7fc363dd93fd] [ 34.400] 19: /usr/bin/Xorg (0x7fc363d8c000+0x52e61) [0x7fc363ddee61] [ 34.400] 20: /usr/bin/Xorg (0x7fc363d8c000+0x41ec5) [0x7fc363dcdec5] [ 34.400] 21: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xfd) [0x7fc361dd9ead] [ 34.400] 22: /usr/bin/Xorg (0x7fc363d8c000+0x4219d) [0x7fc363dce19d] [ 34.400] [ 34.400] [mi] These backtraces from mieqEnqueue may point to a culprit higher up the stack. [ 34.400] [mi] mieq is *NOT* the cause. It is a victim. [ 37.584] [mi] Increasing EQ size to 512 to prevent dropped events. [ 37.585] [mi] EQ processing has resumed after 20 dropped events. [ 37.585] [mi] This may be caused my a misbehaving driver monopolizing the server's resources.