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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Fri, 30 Dec 2022 16:52:36 +0100
Message-ID: <CAJZ5v0iNdLyOpAxsCTTq-zqRfWDrJ5_c2DUcJYE5ZFn7u+2qdQ@mail.gmail.com>
Subject: Re: [RFC][PATCH] ACPI: tracing: Have ACPI debug go to tracing ring buffer
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Joel Fernandes <joel@joelfernandes.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>,
        linux-acpi@vger.kernel.org,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Brian Norris <briannorris@chromium.org>,
        Ross Zwisler <zwisler@google.com>,
        Ching-lin Yu <chinglinyu@google.com>
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On Thu, Dec 15, 2022 at 9:13 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 15 Dec 2022 14:52:48 -0500
> Joel Fernandes <joel@joelfernandes.org> wrote:
>
> > Another approach could be to always enable the trace event by default,
> > if the CONFIG is turned on. Or do a printk() telling the user about
> > the event to enable, so they know why their trace buffer is empty.
>
> Yeah, that is another option.
>
> And, yes I need to document it better. I started to, but then decided to
> hold off until I get some feedback in case this is rejected.
>
> >
> > Up to you and the ACPI maintainers. ;-)
>
> I'm going to guess I may not hear back until the new year. I'm fine with
> that :-)

It's just a couple of days, but still.

Personally, I would use a command line option to control the behavior
and the Kconfig option to provide its default value.

This way it can be flipped without rebuilding the kernel if need be.

I would also make the ACPI debug output go into the trace buffer so
long as the Kconfig option is not changed or the command line option
is not flipped.

Cheers!