[PATCH] PNP / ACPI: Do not return errors if _DIS or _SRS are not present

["Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>]

From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

The ACPI PNP subsystem returns errors from pnpacpi_set_resources()
and pnpacpi_disable_resources() if the _SRS or _DIS methods are not
present, respectively, but it should not do that, because those
methods are optional.  For this reason, modify pnpacpi_set_resources()
and pnpacpi_disable_resources(), respectively, to ignore missing _SRS
or _DIS.

This problem has been uncovered by commit 202317a573b2 (ACPI / scan: Add
acpi_device objects for all device nodes in the namespace) and manifested
itself by causing serial port suspend to fail on some systems.

Fixes: 202317a573b2 (ACPI / scan: Add acpi_device objects for all device nodes in the namespace)
References: https://bugzilla.kernel.org/show_bug.cgi?id=74371
Reported-by: wxg4net <wxg4net@xxxxxxxxx>
Reported-and-tested-by: <nonproffessional@xxxxxxxxx>
Cc: 3.14+ <stable@xxxxxxxxxxxxxxx> # 3.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
 drivers/pnp/pnpacpi/core.c |   44 ++++++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 18 deletions(-)

Index: linux-pm/drivers/pnp/pnpacpi/core.c
===================================================================
--- linux-pm.orig/drivers/pnp/pnpacpi/core.c
+++ linux-pm/drivers/pnp/pnpacpi/core.c
@@ -83,8 +83,7 @@ static int pnpacpi_set_resources(struct
 {
 	struct acpi_device *acpi_dev;
 	acpi_handle handle;
-	struct acpi_buffer buffer;
-	int ret;
+	int ret = 0;
 
 	pnp_dbg(&dev->dev, "set resources\n");
 
@@ -97,19 +96,26 @@ static int pnpacpi_set_resources(struct
 	if (WARN_ON_ONCE(acpi_dev != dev->data))
 		dev->data = acpi_dev;
 
-	ret = pnpacpi_build_resource_template(dev, &buffer);
-	if (ret)
-		return ret;
-	ret = pnpacpi_encode_resources(dev, &buffer);
-	if (ret) {
+	if (acpi_has_method(handle, METHOD_NAME__SRS)) {
+		struct acpi_buffer buffer;
+
+		ret = pnpacpi_build_resource_template(dev, &buffer);
+		if (ret)
+			return ret;
+
+		ret = pnpacpi_encode_resources(dev, &buffer);
+		if (!ret) {
+			acpi_status status;
+
+			status = acpi_set_current_resources(handle, &buffer);
+			if (ACPI_FAILURE(status))
+				ret = -EIO;
+		}
 		kfree(buffer.pointer);
-		return ret;
 	}
-	if (ACPI_FAILURE(acpi_set_current_resources(handle, &buffer)))
-		ret = -EINVAL;
-	else if (acpi_bus_power_manageable(handle))
+	if (!ret && acpi_bus_power_manageable(handle))
 		ret = acpi_bus_set_power(handle, ACPI_STATE_D0);
-	kfree(buffer.pointer);
+
 	return ret;
 }
 
@@ -117,7 +123,7 @@ static int pnpacpi_disable_resources(str
 {
 	struct acpi_device *acpi_dev;
 	acpi_handle handle;
-	int ret;
+	acpi_status status;
 
 	dev_dbg(&dev->dev, "disable resources\n");
 
@@ -128,13 +134,15 @@ static int pnpacpi_disable_resources(str
 	}
 
 	/* acpi_unregister_gsi(pnp_irq(dev, 0)); */
-	ret = 0;
 	if (acpi_bus_power_manageable(handle))
 		acpi_bus_set_power(handle, ACPI_STATE_D3_COLD);
-		/* continue even if acpi_bus_set_power() fails */
-	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_DIS", NULL, NULL)))
-		ret = -ENODEV;
-	return ret;
+
+	/* continue even if acpi_bus_set_power() fails */
+	status = acpi_evaluate_object(handle, "_DIS", NULL, NULL);
+	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
+		return -ENODEV;
+
+	return 0;
 }
 
 #ifdef CONFIG_ACPI_SLEEP

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