Enabling trace points during module load/init

Christian König
2016-12-07T08:28:00Z

Hi everone,

I'm the co-maintainer of the AMD GFX drivers in the upstream kernel and
yesterday I ran into the problem that I need to enable some trace points
during module load/init.

We had that issue quite a bunch of times before, but so far never had
the time or patience to figure out how to enable this properly. So we
always ended up adding printk() into our code additionally to the
existing trace points to figure out what the driver does during startup.

But this time I started to Google a bit and figured out that Steven
Rostedt already had that issue solved years ago, but never pushed it
upstream. Asking Steven why the absolutely surprising answer was that it
was dropped because nobody spoke up and said that this was an useful
feature.

So here I'm absolutely confirming that this is an useful feature and we
could really make good use of it. Also feel free to CC me for reviews
and/or testing.

Best regards,
Christian.