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

[Tony Lindgren <tony@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