Received-SPF: pass (google.com: domain of linux-kernel+bounces-111184-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
Date: Fri, 22 Mar 2024 11:06:57 +0200
From: Tony Lindgren <tony@atomide.com>
To: Nick Bowler <nbowler@draconx.ca>
Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
	regressions@lists.linux.dev, linux-serial@vger.kernel.org
Subject: Re: PROBLEM: Sun Ultra 60 hangs on boot since Linux 6.8
Message-ID: <20240322090657.GD5132@atomide.com>
References: <d84baa5d-a092-3647-8062-ed7081d329d4@draconx.ca>
 <20240322051531.GA5132@atomide.com>
 <d7337014-09ac-8a35-7159-e75ecd2707b6@draconx.ca>
 <20240322064843.GC5132@atomide.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240322064843.GC5132@atomide.com>

* Tony Lindgren <tony@atomide.com> [240322 08:48]:
> * Nick Bowler <nbowler@draconx.ca> [240322 06:36]:
> > On 2024-03-22 01:15, Tony Lindgren wrote:
> > > Can you please test if the following change to add back the check for
> > > !pm_runtime_active() is enough to fix the issue?
> > 
> > I applied the below patch on top of 6.8 and unfortunately it does _not_
> > fix the problem (no obvious change in behaviour).
> 
> Hmm OK thanks for testing. I'll take a look and see if I can debug this
> with qemu sparc as I no longer have any sparc boxes around.

I can't reproduce this on qemu-system-sparc64, probably as it does not use
the sunsab driver.

I noticed something though, I think we need to test for the port device
instead for being runtime PM enabled.

Can you please test if the updated patch below make things work again?

Regards,

Tony

8< -------------------
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -156,7 +156,7 @@ static void __uart_start(struct uart_state *state)
 	 * enabled, serial_port_runtime_resume() calls start_tx() again
 	 * after enabling the device.
 	 */
-	if (pm_runtime_active(&port_dev->dev))
+	if (!pm_runtime_enabled(port->dev) || pm_runtime_active(&port_dev->dev))
 		port->ops->start_tx(port);
 	pm_runtime_mark_last_busy(&port_dev->dev);
 	pm_runtime_put_autosuspend(&port_dev->dev);
-- 
2.44.0