4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hans de Goede <hdegoede@xxxxxxxxxx> [ Upstream commit 7d09995dcb0577b4a56aad7f2bb56f28604e8f1a ] ACPI enumerated serdev-controllers do not have an ACPI companion, the ACPI companion belongs to the serdev-device child of the serdev-controller, not to the controller itself. This was causing serdev_uevent to always return -ENODEV when called on a serdev-controller leading to errors like these: kernel: serial serial0: uevent: failed to send synthetic uevent being logged. This commit modifies serdev_uevent to directly return 0 when called on an ACPI enumerated serdev-controller fixing this. Note: I do not think that setting a modalias on a devicetree enumerated serdev-controller makes sense either. So perhaps the !dev->of_node part of the check can be dropped too, but I'm not entirely sure that doing this on devicetree too is correct. Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Acked-by: Johan Hovold <johan@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serdev/core.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/tty/serdev/core.c +++ b/drivers/tty/serdev/core.c @@ -54,6 +54,11 @@ static int serdev_uevent(struct device * int rc; /* TODO: platform modalias */ + + /* ACPI enumerated controllers do not have a modalias */ + if (!dev->of_node && dev->type == &serdev_ctrl_type) + return 0; + rc = acpi_device_uevent_modalias(dev, env); if (rc != -ENODEV) return rc;