[PATCH] tty/serial/8250: Request driver probe from an async task

[Paul Menzel]

Currently, according to `initcall_debug` running `serial8250_init` takes
around 33 ms on a Lenovo X60 and TUXEDO Book BU1406.

As this is in the critical path, and most distributions do *not* build
*8250* as a module, that means `CONFIG_SERIAL_8250=y`, probe the device
asynchronously, so other tasks are not hold up.

Signed-off-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
---
 drivers/tty/serial/8250/8250_core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 9342fc2ee7df..996de9c78001 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -894,6 +894,7 @@ static struct platform_driver serial8250_isa_driver = {
 	.driver		= {
 		.name	= "serial8250",
 	},
+	.driver.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 };
 
 /*
-- 
2.14.1


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