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Date:   Tue, 16 Jun 2020 09:38:27 +0200
From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     Stephen Berman <stephen.berman@gmx.net>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org
Subject: Re: power-off delay/hang due to commit 6d25be57 (mainline)
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On 2020-06-16 09:14:37 [+0200], Stephen Berman wrote:
> 
> I set CONFIG_ACPI_DEBUG=y, applied the patch and rebuilt 5.6.4, but:
> 
> $ cat /sys/kernel/debug/tracing/trace > trace.txt
> cat: /sys/kernel/debug/tracing/trace: No such file or directory
> 
> Here are all the 5.6.4 config options with "TRACING" or "TRACE"; do I
> need to set any that aren't set?

I see that "Kernel hacking  ---> Tracers" is enabled. You should have
one tracer enabled for that trace_printk() to work. You have context
switch tracer so it should be enough.

You might need CONFIG_DEBUG_FS (but it is set in your 5.1 config) or it
is just not mounted. So I have here:

| debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime)
| tracefs on /sys/kernel/debug/tracing type tracefs (rw,nosuid,nodev,noexec,relatime)

Does it work for you if you mount it?

> Steve Berman

Sebastian