[Intel-gfx] [igt RFC 2/3] lib: Add hooks for enabling ftrace

[Chris Wilson]

Quoting Chris Wilson (2017-10-13 13:02:58)
> If the kernel has tracing support builtin, we can enable around
> troublesome tests to obtain greater detail from the kernel that may
> prove invaluable in debugging the problem.

Michał pointed out that there is a ftrace-dump-on-oops flag, which could
very well be a way we can vastly increase debug output without
increasing the noise. The challenge is putting it to use. We could start
with a plain function_tracer and see where we need to go from there; I
think we want to trace_printk() (as possibly a igt_trace_printk if we
want to go overboard).
-Chris