[alsa-devel] How to show hda trace events in a self-built kernel?

[David Henningsson]

On 2014-04-23 09:35, Lin, Mengdong wrote:
> Hi,
>
> How to show hda trace events in a self-built kernel?
>
> With a self-built kernel under Ubuntu 13.04 or 13.10, I enabled hda
> trace events by
>
> #cd /sys/kernel/debug/tracing/
>
> #echo 1 > events/hda/enable
>
> #echo 1 > events/had_intel/enable
>
> Then I check the codec proc entry and run “cat trace”. But I got no
> output of the hda trace events.

Did you forget to do:
# echo 1 > tracing_on

You might also want to set current_tracer to something.

Otherwise I don't know what the problem can be.

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic