On grid the sampler sat 42 minutes in runtime_pollWait on the Arc A380's
hwmon fan1_input: kernfs accepts epoll, so os.ReadFile made the fd
non-blocking, i915 answered EAGAIN once, and the poller waited for a
readiness kernfs only signals on sysfs_notify. Every graph on the machine
froze while the API carried on.
readStr now reads with plain blocking syscalls. Each GPU's sysfs reads run
under a three-second deadline; a device that does not answer is marked
stalled, logged, and left alone until restart, with the box saying so.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
