Re: PROBLEM: Sun Ultra 60 hangs on boot since Linux 6.8

[Nick Bowler <nbowler@draconx.ca>]

On 2024-03-22 01:15, Tony Lindgren wrote:
> * Nick Bowler <nbowler@draconx.ca> [240322 04:29]:
>> I bisected to this commit:
>> 
>>   commit 45a3a8ef81291b63a2b50a1a145857dd9fc05e89
>>   Author: Tony Lindgren <tony@atomide.com>
>>   Date:   Mon Nov 13 10:07:53 2023 +0200
>>   
>>       serial: core: Revert checks for tx runtime PM state
>> 
>> Reverting this commit on top of Linux 6.8 is sufficient to get the
>> system booting again.
> 
> Thanks a lot for bisecting and reporting the issue.
> 
> 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).

Thanks,
  Nick

> 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->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);