Comment 10 for bug 1526657

Below is the information from Xorg.O.log.old (about the described lock, on Nov. 21st):

[141735.156] nouveau_exa_download_from_screen:295 - falling back to memcpy ignores tiling
[141735.188] (EE)
[141735.188] (EE) Backtrace:
[141735.198] (EE) 0: /usr/bin/Xorg (xorg_backtrace+0x56) [0x7fde93b52d46]
[141735.198] (EE) 1: /usr/bin/Xorg (0x7fde9399c000+0x1baf29) [0x7fde93b56f29]
[141735.198] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7fde91690000+0x35180) [0x7fde916c5180]
[141735.198] (EE) 3: /lib/x86_64-linux-gnu/libc.so.6 (0x7fde91690000+0x90720) [0x7fde91720720]
[141735.198] (EE) 4: /usr/lib/xorg/modules/libexa.so (0x7fde8d794000+0x533e) [0x7fde8d79933e]
[141735.198] (EE) 5: /usr/lib/xorg/modules/libexa.so (0x7fde8d794000+0x5803) [0x7fde8d799803]
[141735.198] (EE) 6: /usr/lib/xorg/modules/libexa.so (0x7fde8d794000+0x7e9f) [0x7fde8d79be9f]
[141735.198] (EE) 7: /usr/lib/xorg/modules/libexa.so (0x7fde8d794000+0x11a46) [0x7fde8d7a5a46]
[141735.198] (EE) 8: /usr/lib/xorg/modules/libexa.so (0x7fde8d794000+0xe870) [0x7fde8d7a2870]
[141735.198] (EE) 9: /usr/lib/xorg/modules/libexa.so (0x7fde8d794000+0xecf3) [0x7fde8d7a2cf3]
[141735.198] (EE) 10: /usr/bin/Xorg (0x7fde9399c000+0x13d3b1) [0x7fde93ad93b1]
[141735.198] (EE) 11: /usr/lib/xorg/modules/libexa.so (0x7fde8d794000+0xc2a0) [0x7fde8d7a02a0]
[141735.198] (EE) 12: /usr/bin/Xorg (0x7fde9399c000+0x13d643) [0x7fde93ad9643]
[141735.198] (EE) 13: /usr/bin/Xorg (0x7fde9399c000+0x133587) [0x7fde93acf587]
[141735.199] (EE) 14: /usr/bin/Xorg (0x7fde9399c000+0x573f7) [0x7fde939f33f7]
[141735.199] (EE) 15: /usr/bin/Xorg (0x7fde9399c000+0x5b596) [0x7fde939f7596]
[141735.199] (EE) 16: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf5) [0x7fde916b1b45]
[141735.199] (EE) 17: /usr/bin/Xorg (0x7fde9399c000+0x4590e) [0x7fde939e190e]
[141735.199] (EE)
[141735.200] (EE) Segmentation fault at address 0x0
[141735.200] (EE)
Fatal server error:
[141735.200] (EE) Caught signal 11 (Segmentation fault). Server aborting
[141735.200] (EE)
[141735.201] (EE)
Please consult the The X.Org Foundation support
     at http://wiki.x.org
 for help.
[141735.201] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[141735.201] (EE)
[141735.202] (II) AIGLX: Suspending AIGLX clients for VT switch
[141735.203] (II) NOUVEAU(0): NVLeaveVT is called.
[141735.260] (EE) Server terminated with error (1). Closing log file.