[ 037/117] ACPI / LPSS: dont crash if a device has no MMIO resources

[Greg Kroah-Hartman]

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

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

From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>

commit af65cfe9aeae03e0682bebdf4db94582d75562dd upstream.

Intel LPSS devices that are enumerated from ACPI have both MMIO and IRQ
resources returned in their _CRS method. However, Apple Macbook Air with
Haswell has LPSS devices enumerated from PCI bus instead and _CRS method
returns only an interrupt number (but the device has _HID set that causes
the scan handler to match it).

The current ACPI / LPSS code sets pdata->dev_desc only when MMIO resource
is found for the device and in case of Macbook Air it is never found. That
leads to a NULL pointer dereference in register_device_clock().

Correct this by always setting the pdata->dev_desc.

Reported-and-tested-by: Imre Kaloz <kaloz@xxxxxxxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/acpi/acpi_lpss.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -257,12 +257,13 @@ static int acpi_lpss_create_device(struc
 				pdata->mmio_size = resource_size(&rentry->res);
 			pdata->mmio_base = ioremap(rentry->res.start,
 						   pdata->mmio_size);
-			pdata->dev_desc = dev_desc;
 			break;
 		}
 
 	acpi_dev_free_resource_list(&resource_list);
 
+	pdata->dev_desc = dev_desc;
+
 	if (dev_desc->clk_required) {
 		ret = register_device_clock(adev, pdata);
 		if (ret) {


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