releases/4.15.17/serdev-fix-serdev_uevent-failure-on-acpi-enumerated-serdev-controllers.patch

   1 From foo@baz Mon Apr  9 10:16:32 CEST 2018
   2 From: Hans de Goede <hdegoede@redhat.com>
   3 Date: Mon, 25 Dec 2017 21:50:45 +0100
   4 Subject: serdev: Fix serdev_uevent failure on ACPI enumerated serdev-controllers
   5
   6 From: Hans de Goede <hdegoede@redhat.com>
   7
   8
   9 [ Upstream commit 7d09995dcb0577b4a56aad7f2bb56f28604e8f1a ]
  10
  11 ACPI enumerated serdev-controllers do not have an ACPI companion, the ACPI
  12 companion belongs to the serdev-device child of the serdev-controller, not
  13 to the controller itself. This was causing serdev_uevent to always return
  14 -ENODEV when called on a serdev-controller leading to errors like these:
  15
  16 kernel: serial serial0: uevent: failed to send synthetic uevent
  17
  18 being logged. This commit modifies serdev_uevent to directly return 0
  19 when called on an ACPI enumerated serdev-controller fixing this.
  20
  21 Note: I do not think that setting a modalias on a devicetree enumerated
  22 serdev-controller makes sense either. So perhaps the !dev->of_node part of
  23 the check can be dropped too, but I'm not entirely sure that doing this
  24 on devicetree too is correct.
  25
  26 Signed-off-by: Hans de Goede <hdegoede@redhat.com>
  27 Acked-by: Johan Hovold <johan@kernel.org>
  28 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  29 Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
  30 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  31 ---
  32  drivers/tty/serdev/core.c |    5 +++++
  33  1 file changed, 5 insertions(+)
  34
  35 --- a/drivers/tty/serdev/core.c
  36 +++ b/drivers/tty/serdev/core.c
  37 @@ -54,6 +54,11 @@ static int serdev_uevent(struct device *
  38         int rc;
  39
  40         /* TODO: platform modalias */
  41 +
  42 +       /* ACPI enumerated controllers do not have a modalias */
  43 +       if (!dev->of_node && dev->type == &serdev_ctrl_type)
  44 +               return 0;
  45 +
  46         rc = acpi_device_uevent_modalias(dev, env);
  47         if (rc != -ENODEV)
  48                 return rc;