PCI: ignore bit0 of _OSC return code

Currently acpi_run_osc() checks all the bits in _OSC result code (the
first DWORD in the capabilities buffer) to see error condition. But the
bit 0, which doesn't indicate any error, must be ignored.

The bit 0 is used as the query flag at _OSC invocation time. Some
platforms clear it during _OSC evaluation, but the others don't. On
latter platforms, current acpi_run_osc() mis-detects error when _OSC is
evaluated with query flag set because it doesn't ignore the bit 0.
Because of this, the __acpi_query_osc() always fails on such platforms.

And this is the cause of the problem that pci_osc_control_set() doesn't
work since the commit 4e39432f which
changed pci_osc_control_set() to use __acpi_query_osc().
Tested-by: "Tomasz Czernecki <czernecki@gmail.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/pci-acpi.c

@@ -63,7 +63,7 @@ static acpi_status acpi_run_osc(acpi_handle handle,
 	union acpi_object in_params[4];
 	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 	union acpi_object *out_obj;
-	u32 osc_dw0, flags = osc_args->capbuf[OSC_QUERY_TYPE];
+	u32 errors, flags = osc_args->capbuf[OSC_QUERY_TYPE];
 
 	/* Setting up input parameters */
 	input.count = 4;
@@ -92,15 +92,16 @@ static acpi_status acpi_run_osc(acpi_handle handle,
 		status = AE_TYPE;
 		goto out_kfree;
 	}
-	osc_dw0 = *((u32 *)out_obj->buffer.pointer);
-	if (osc_dw0) {
-		if (osc_dw0 & OSC_REQUEST_ERROR)
+	/* Need to ignore the bit0 in result code */
+	errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
+	if (errors) {
+		if (errors & OSC_REQUEST_ERROR)
 			printk(KERN_DEBUG "_OSC request fails\n"); 
-		if (osc_dw0 & OSC_INVALID_UUID_ERROR)
+		if (errors & OSC_INVALID_UUID_ERROR)
 			printk(KERN_DEBUG "_OSC invalid UUID\n"); 
-		if (osc_dw0 & OSC_INVALID_REVISION_ERROR)
+		if (errors & OSC_INVALID_REVISION_ERROR)
 			printk(KERN_DEBUG "_OSC invalid revision\n"); 
-		if (osc_dw0 & OSC_CAPABILITIES_MASK_ERROR) {
+		if (errors & OSC_CAPABILITIES_MASK_ERROR) {
 			if (flags & OSC_QUERY_ENABLE)
 				goto out_success;
 			printk(KERN_DEBUG "_OSC FW not grant req. control\n");