[linux-libre] Critical hangs with nouveau 2D acceleration under 5.10
When 2D acceleration is enabled through nouveau (default), the computer freezes and becomes unresponsive. Occasionally remote access is still possible, but this is not always the case. In most cases, I wasn't doing anything particularly graphically intensive. In one instance, it locked up while I was away, simply streaming audio from the machine.
Adding the kernel parameter `nouveau.noaccel=1` prevents this failure.
Kernel logging on this failure is hit-or-miss... sometimes I get a `kmem_cache_alloc_trace` (as seen in the attached log) and others the logs stop after the line following `general protection fault, probably for non-canonical address`.
I spent some time running through some nouveau tweaks with a developer in #nouveau—they ultimately concluded that it is not a nouveau bug, and that nouveau is simply getting hosed by another problem (see a similar trace for btrfs in the kernel log).
I first encountered this at least a year ago, but at the time simply disabled 2d accel... as such, I am not sure what the first affected version is. Nonetheless, I have yet to run into this using the LTS kernel, thus my belief that this is a kernel issue.
My GPU is a GeForce GTX 670 (Kepler)
Attached are a (truncated; see note for full text) kernel log (with `drm.debug=14 log_buf_len=16M`, per nouveau debug suggestions), Xorg log, and my (minimal) Xorg config.