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@canonical.com] Sent: Wednesday, April 23, 2014 4:32 PM To: Lin, Mengdong; alsa-devel@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