From 6f699743aebf07538e506a46c5965eb8bdd2c716 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Mon, 23 Oct 2023 10:48:54 +0300 Subject: [PATCH] serial: core: Fix runtime PM handling for pending tx Richard reported that a serial port may end up sometimes with tx data pending in the buffer for long periods of time. Turns out we bail out early on any errors from pm_runtime_get(), including -EINPROGRESS. To fix the issue, we need to ignore -EINPROGRESS as we only care about the runtime PM usage count at this point. We check for an active runtime PM state later on for tx. Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Cc: stable Reported-by: Richard Purdie Cc: Bruce Ashfield Cc: Mikko Rapeli Cc: Paul Gortmaker Cc: Randy MacLeod Signed-off-by: Tony Lindgren Tested-by: Richard Purdie Link: https://lore.kernel.org/r/20231023074856.61896-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index b106eb3943d0..f1348a509552 100644 --- 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; }