Trying to run a Youtube clip in Firefox:

(I managed to get these out of journalctl)

Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0]  ERROR nsource:
DATA_ERROR nstatus: BAD_ARGUMENT
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0] ch 3
[plugin-containe[901]] subc 7 class 0x0697 mthd 0x0208 data 0x00000120
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0]  ERROR nsource:
LIMIT_COLOR nstatus: BAD_ARGUMENT PROTECTION_FAULT
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0] ch 3
[plugin-containe[901]] subc 7 class 0x0697 mthd 0x0204 data 0x00b80000
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0]  ERROR nsource:
DATA_ERROR nstatus: BAD_ARGUMENT PROTECTION_FAULT
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0] ch 3
[plugin-containe[901]] subc 7 class 0x0697 mthd 0x0208 data 0x00000120
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0]  ERROR nsource:
DATA_ERROR nstatus: BAD_ARGUMENT PROTECTION_FAULT
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0] ch 3
[plugin-containe[901]] subc 7 class 0x0697 mthd 0x0208 data 0x00000120
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0]  ERROR nsource:
DATA_ERROR nstatus: BAD_ARGUMENT PROTECTION_FAULT
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0] ch 3
[plugin-containe[901]] subc 7 class 0x0697 mthd 0x0208 data 0x00000120
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0]  ERROR nsource:
DATA_ERROR nstatus: BAD_ARGUMENT PROTECTION_FAULT
Jan 07 14:48:59 Delta kernel: nouveau E[  PGRAPH][0000:01:00.0] ch 3
[plugin-containe[901]] subc 7 class 0x0697 mthd 0x0208 data 0x00000120

Versions:
libdrm 2.4.50-1
mesa 10.0.1-2
xorg-server 1.14.5-1
xf86-video-nouveau 1.0.10-1
kernel 3.13.0-rc7-00055-gef350bb