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

[Lin, Mengdong]

Thanks, David!

tracing_on is '1' by default and current_tracer is 'nop', same for both kernels.

I also notice the 'net' trace event output is okay on the same kernel on which I cannot get hda trace event output.

Regards
Mengdong

> -----Original Message-----
> From: David Henningsson [mailto:david.henningsson at canonical.com]
> Sent: Wednesday, April 23, 2014 4:32 PM
> To: Lin, Mengdong; alsa-devel at alsa-project.org
> Subject: Re: How to show hda trace events in a self-built kernel?
> 
> 
> 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