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

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@gmail.com>
Reported-and-tested-by: <nonproffessional@gmail.com>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 26 insertions, 18 deletions

diff --git a/drivers/pnp/pnpacpi/core.c b/drivers/pnp/pnpacpi/core.c
index 9f611cbbc294..c31aa07b3ba5 100644
--- a/drivers/pnp/pnpacpi/core.c
+++ b/drivers/pnp/pnpacpi/core.c
@@ -83,8 +83,7 @@ static int pnpacpi_set_resources(struct pnp_dev *dev)
 {
         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 pnp_dev *dev)
         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(struct pnp_dev *dev)
 {
         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(struct pnp_dev *dev)
         }
 
         /* 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