Enabling trace points during module load/init

From: Christian KÃnig
Date: Wed Dec 07 2016 - 03:28:16 EST


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.