[IN DISCUSSION, NOT MERGE]case-lib: redirect nohup stdout and stderr to /dev/null

[aiChaoSONG]

If only redirect nohup stdout to /dev/null, we will see
'nohup: redirecting stderr to stdout' message from nohup
when manually run './check-kmod-load-unload.sh -l1'.

Which will make the test log looks ugly.

Signed-off-by: Amery Song chao.song@intel.com

[libinyang]

LGTM

[Bin-QA]

I don't this this patch will meet your requirement, because
when you add '&' for nohup command it will create 'nohup.out' file for stdout & stderr

[aiChaoSONG]

I don't this this patch will meet your requirement, because
when you add '&' for nohup command it will create 'nohup.out' file for stdout & stderr

@Bin-QA Any suggestions？ because “nohup: redirecting stderr to stdout” in the test log， which makes the log ugly， and I test this pr on helios， the output of nohup disappeared.

[Bin-QA]

@Bin-QA Any suggestions？ because “nohup: redirecting stderr to stdout” in the test log， which makes the log ugly， and I test this pr on helios， the output of nohup disappeared.

because you will create 'nohup.out' at your current folder

[xiulipan]

@aiChaoSONG will this bring us trouble with debug? As error message is gone

[aiChaoSONG]

@Bin-QA When we run sof-test, the repo is cloned to local, so all command is running locally, then why we need a nohup here?

[Bin-QA]

@aiChaoSONG because here need recreate pulseaudio command,
Notice: here recreate pulseaudio is all command , so it is not limited the system server
So when you terminal quit, the command attach for your terminal will be killed
the nohup command use to avoid terminal/parent process quit problem

[marc-hb]

Which will make the test log looks ugly.

Test logs are not meant to be beautiful, they have to be informative and not too noisy. That does not seem like a lot of noise, is it?

Logs that are really noisy should be redirected to a file, tests should almost never redirect anything to >/dev/null. In case of a failure any information could be useful.

EDIT: I detailed why I think /dev/null is a bad habit in this unrelated PR: thesofproject/sof#2711 (comment)

I have a larger question: why is this script not using systemctl? https://docs.ubuntu.com/core/en/stacks/audio/pulseaudio/docs/using-pulseaudio
Is this script not running on Ubuntu?

[marc-hb]

I have a larger question: why is this script not using systemctl? https://docs.ubuntu.com/core/en/stacks/audio/pulseaudio/docs/using-pulseaudio

OK, this doc is obsolete, sorry. I found this more accurate one, tested it and verified it is up to date wrt. Ubuntu 18.04
https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Running/

Why is the nohup needed at all? I ran pulseaudio --start over ssh with no autospawn and it worked without nohup.

Also wondering why use kill -KILL $(ps) instead of a simpler pulseaudio --kill?

Why use ps instead of pulseaudio --check?

Why try to extract command line parameters from ps as opposed to rely on regular config files?

Also why manually restart pulseaudio after restoring the autospawn which already starts it when needed?

[aiChaoSONG]

@Bin-QA Could you please help to answer Marc's questions?

[Bin-QA]

@marc-hb because we are not sure target machine how to configure the pulseaudio
the end user (current just us) maybe not start pulseaudio or something
so it detect in ps if target machine configure more pulseaudio version,
how to trace them and restore them also is the problem (normally it will refer configure and test pulseaudio)
we want the script in here is more common to use

[marc-hb]

I'm not sure I follow, are you afraid some operating system(s) hide(s) some pulseaudio --parameters outside the normal pulseaudio configuration files?

How many different operating system versions is sof-test regularly used on? I didn't see any mentioned in https://github.com/thesofproject/sof-test/blob/master/README.md

[xiulipan]

@aiChaoSONG @macchian any update? Do we still need this

[aiChaoSONG]

No, let's close this, the issue I want to address by this PR is not reproduced. maybe already fixed by other PR