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From:   John Ogness <john.ogness@linutronix.de>
To:     todd.e.brandt@linux.intel.com, pmladek@suse.com
Cc:     linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
        senozhatsky@chromium.org, rostedt@goodmis.org
Subject: Re: PNP0501 serial driver takes almost 2 seconds to suspend/resume
 (printk issue)
In-Reply-To: <51b9e2cc3baf61a604bd239b736ec2d12f1f6695.camel@linux.intel.com>
References: <12fb98fe27e23e3f74a139e5e8eb83a97a343372.camel@linux.intel.com>
 <51b9e2cc3baf61a604bd239b736ec2d12f1f6695.camel@linux.intel.com>
Date:   Fri, 08 Jul 2022 10:07:08 +0206
Message-ID: <87czegxccb.fsf@jogness.linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Hi Todd,

Thanks for reporting this.

On 2022-07-07, Todd Brandt <todd.e.brandt@linux.intel.com> wrote:
> Ever since 5.19.0-rc1 the serial device has taken almost a second
> longer in both suspend and resume. This effect is witnessed in half
> the machines in our lab (~10 machines). It occurs on dell, asus,
> gigabyte and other machines so it's not hardware specific.

Please provide a full dmesg log if you can. The important parts of the
log would be:

- boot arguments
- any lines with "printk" in it
- timing information
- messages during suspend and resume

pr_flush() uses a timeout of 1 second. I assume your console driver is
not printing and therefore not making any forward progress.

John Ogness