linux-kernel - [PATCH 4.18 105/197] ACPI / scan: Initialize status to ACPI_STA

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Date:   Thu, 13 Sep 2018 15:30:54 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hans de Goede <hdegoede@...hat.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.18 105/197] ACPI / scan: Initialize status to ACPI_STA_DEFAULT

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hans de Goede <hdegoede@...hat.com>

[ Upstream commit 5971b0c1594d6c34e257101ed5fdffec65205c50 ]

Since commit 63347db0affa "ACPI / scan: Use acpi_bus_get_status() to
initialize ACPI_TYPE_DEVICE devs" the status field of normal acpi_devices
gets set to 0 by acpi_bus_type_and_status() and filled with its actual
value later when acpi_add_single_object() calls acpi_bus_get_status().

This means that any acpi_match_device_ids() calls in between will always
fail with -ENOENT.

We already have a workaround for this, which temporary forces status to
ACPI_STA_DEFAULT in drivers/acpi/x86/utils.c: acpi_device_always_present()
and the next commit in this series adds another acpi_match_device_ids()
call between status being initialized as 0 and the acpi_bus_get_status()
call.

Rather then adding another workaround, this commit makes
acpi_bus_type_and_status() initialize status to ACPI_STA_DEFAULT, this is
safe to do as the only code looking at status between the initialization
and the acpi_bus_get_status() call is those acpi_match_device_ids() calls.

Note this does mean that we need to (re)set status to 0 in case the
acpi_bus_get_status() call fails.

Signed-off-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/acpi/scan.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1612,7 +1612,8 @@ static int acpi_add_single_object(struct
 	 * Note this must be done before the get power-/wakeup_dev-flags calls.
 	 */
 	if (type == ACPI_BUS_TYPE_DEVICE)
-		acpi_bus_get_status(device);
+		if (acpi_bus_get_status(device) < 0)
+			acpi_set_device_status(device, 0);

 	acpi_bus_get_power_flags(device);
 	acpi_bus_get_wakeup_device_flags(device);
@@ -1690,7 +1691,7 @@ static int acpi_bus_type_and_status(acpi
 		 * acpi_add_single_object updates this once we've an acpi_device
 		 * so that acpi_bus_get_status' quirk handling can be used.
 		 */
-		*sta = 0;
+		*sta = ACPI_STA_DEFAULT;
 		break;
 	case ACPI_TYPE_PROCESSOR:
 		*type = ACPI_BUS_TYPE_PROCESSOR;