* Richard Purdie <richard.purdie@xxxxxxxxxxxxxxxxxxx> [231016 08:10]:
> The port sometimes doesn't come up properly at boot.
>
> To be clear, the "\n\n" from the qemu side into the port doesn't seem
> to help. The "echo helloB > /dev/ttyS1" inside the image does seem to
> wake it up.
So if I understand correctly, this issue still happens with kernel patched
with commit 81a61051e0ce ("serial: core: Fix checks for tx runtime PM
state"), and the issue now only happens sometimes.
I wonder if the following additional change might help?
I have not yet tried to reproduce with the full test case you guys have,
just with qemu and two ports but no luck so far with a minimal test case.
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
@@ -146,7 +146,7 @@ static void __uart_start(struct uart_state *state)
/* Increment the runtime PM usage count for the active check below */
err = pm_runtime_get(&port_dev->dev);
- if (err < 0) {
+ if (err < 0 && err != -EINPROGRESS) {
pm_runtime_put_noidle(&port_dev->dev);
return;
}
