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Date: Sat, 23 Mar 2024 08:49:25 +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: <20240323064925.GE5132@atomide.com>
References: <d84baa5d-a092-3647-8062-ed7081d329d4@draconx.ca>
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* Nick Bowler <nbowler@draconx.ca> [240322 14:12]:
> On 2024-03-22 05:06, Tony Lindgren wrote:
> [...]
> > 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?
> 
> Yes, with the below patch applied on top of 6.8 things are working.

OK great thanks for testing, I'll send out a proper patch.

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)