Edit: Correction, The crash was not related to nvidia, but I have seen those Xid messages in my dmesg nevertheless.
My laptop crashed again (hard crash, no sysrq possible, so most probably graphics related).
This may be related
Mar 19 22:34:35 localhost kernel: [39218.242039] NVRM: Xid (0000:02:00): 56, CMDre 00000003 000000c0 b0ef122d 00000007 00000000
Mar 19 22:34:35 localhost kernel: [39218.242054] NVRM: Xid (0000:02:00): 56, CMDre 00000004 000000c0 b0ef122d 00000007 00000000
Above message was in my kernel log. That looks to be related to nvidia.
I am also attaching a bug report generated from nvidia-bug-report.