From: Radim Krčmář Date: Fri, 29 May 2015 20:18:52 +0000 (+0200) Subject: pvpanic: handle missing _STA correctly X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=55cd3f01d631b0a3a022393bac234b9a643301f6;p=deliverable%2Flinux.git pvpanic: handle missing _STA correctly pvpanic was not properly detected when _STA was missing. ACPI 6.0 April 2015, 6.3.7 _STA (Status) If a device object (including the processor object) does not have an _STA object, then OSPM assumes that all of the above bits are set (i.e., the device is present, enabled, shown in the UI, and functioning). Not adhering to the specification made pvpanic dormant under QEMU 2.3. The original patch used acpi_bus_get_status_handle, which was not being exported, so module build blew up; switch to acpi_bus_get_status and use the status it populates. Populated status is a bitfield so we can make the code self-documenting. We do not check 'present' because 'enabled' has to be false in that case by specification. Older QEMUs set 0xff to status and newer ones do 0xb. Suggested-by: Igor Mammedov Signed-off-by: Radim Krčmář Reviewed-by: Igor Mammedov [dvhart@linux.intel.com: Merge acpi_bug_get_status fix to avoid bisect breakage] Signed-off-by: Darren Hart --- diff --git a/drivers/platform/x86/pvpanic.c b/drivers/platform/x86/pvpanic.c index 073a90a63dbc..fd86daba7ffd 100644 --- a/drivers/platform/x86/pvpanic.c +++ b/drivers/platform/x86/pvpanic.c @@ -92,13 +92,13 @@ pvpanic_walk_resources(struct acpi_resource *res, void *context) static int pvpanic_add(struct acpi_device *device) { - acpi_status status; - u64 ret; + int ret; - status = acpi_evaluate_integer(device->handle, "_STA", NULL, - &ret); + ret = acpi_bus_get_status(device); + if (ret < 0) + return ret; - if (ACPI_FAILURE(status) || (ret & 0x0B) != 0x0B) + if (!device->status.enabled || !device->status.functional) return -ENODEV; acpi_walk_resources(device->handle, METHOD_NAME__CRS,