[mi] EQ overflowing.  Additional events will be discarded until existing events are processed.

Backtrace:
0: /usr/bin/X (xorg_backtrace+0x3d) [0x7fb6e0a4802d]
1: /usr/bin/X (mieqEnqueue+0x22b) [0x7fb6e0a29f6b]
2: /usr/bin/X (QueuePointerEvents+0x52) [0x7fb6e09116d2]
3: /usr/lib/xorg/modules/input/evdev_drv.so (0x7fb6d643d000+0x566f) [0x7fb6d644266f]
4: /usr/bin/X (0x7fb6e08a6000+0x91af8) [0x7fb6e0937af8]
5: /usr/bin/X (0x7fb6e08a6000+0xba520) [0x7fb6e0960520]
6: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7fb6df9a6000+0xfbb0) [0x7fb6df9b5bb0]
7: /lib/x86_64-linux-gnu/libc.so.6 (ioctl+0x7) [0x7fb6de6b22f7]
8: /usr/lib/x86_64-linux-gnu/libdrm.so.2 (drmIoctl+0x34) [0x7fb6df79d364]
9: /usr/lib/x86_64-linux-gnu/libdrm.so.2 (drmCommandWriteRead+0x1f) [0x7fb6df79f68f]
10: /usr/lib/x86_64-linux-gnu/libdrm_radeon.so.1 (0x7fb6da2fc000+0x26af) [0x7fb6da2fe6af]
11: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7fb6da509000+0x444f8) [0x7fb6da54d4f8]
12: /usr/lib/xorg/modules/drivers/radeon_drv.so (0x7fb6da509000+0x44970) [0x7fb6da54d970]
13: /usr/bin/X (_CallCallbacks+0x34) [0x7fb6e08ff9e4]
14: /usr/bin/X (FlushAllOutput+0x2b) [0x7fb6e0a4b35b]
15: /usr/bin/X (0x7fb6e08a6000+0x54eb3) [0x7fb6e08faeb3]
16: /usr/bin/X (0x7fb6e08a6000+0x4456a) [0x7fb6e08ea56a]
17: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf5) [0x7fb6de5e1de5]
18: /usr/bin/X (0x7fb6e08a6000+0x448af) [0x7fb6e08ea8af]

[mi] These backtraces from mieqEnqueue may point to a culprit higher up the stack.
[mi] mieq is *NOT* the cause.  It is a victim.