Comment 92 for bug 1098489

I can't test it, obviously.
The rotated zaphod screen, at which the artefacts appear in my case, is only available with "sna" enabled.

On a side note:
I tried it nevertheless as I forgot about that.
The result was a segfault of the xserver.

[ 406.336] Requested Entity already in use!
[ 406.336] (EE) Screen 1 deleted because of no matching config section.
[ 406.336] (EE)
[ 406.336] (EE) Backtrace:
[ 406.336] (EE) 0: /usr/bin/X (xorg_backtrace+0x36) [0x58a416]
[ 406.336] (EE) 1: /usr/bin/X (0x400000+0x18e269) [0x58e269]
[ 406.336] (EE) 2: /usr/lib/libpthread.so.0 (0x7f3cfacee000+0xf1e0) [0x7f3cfacfd1e0]
[ 406.336] (EE) 3: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f3cf84d2000+0x16150) [0x7f3cf84e8150]
[ 406.336] (EE) 4: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f3cf84d2000+0x17435) [0x7f3cf84e9435]
[ 406.336] (EE) 5: /usr/bin/X (xf86DeleteScreen+0x84) [0x480c64]
[ 406.336] (EE) 6: /usr/bin/X (xf86BusConfig+0x216) [0x46c086]
[ 406.336] (EE) 7: /usr/bin/X (InitOutput+0x956) [0x479df6]
[ 406.336] (EE) 8: /usr/bin/X (0x400000+0x26776) [0x426776]
[ 406.336] (EE) 9: /usr/lib/libc.so.6 (__libc_start_main+0xf5) [0x7f3cf9b7aa15]
[ 406.336] (EE) 10: /usr/bin/X (0x400000+0x26c9d) [0x426c9d]
[ 406.336] (EE)
[ 406.336] (EE) Segmentation fault at address 0x0
[ 406.336]
Fatal server error:
[ 406.336] Caught signal 11 (Segmentation fault). Server aborting
[ 406.336]
[ 406.336] (EE)

Wouldn't it be possible to gracefully exit and remind users that rotated setups are only available with the "sna" option?