On Mon, Feb 10, 2014 at 11:39:29PM +0100, Rafael J. Wysocki wrote:
> > _STA() returns 0x0A instead of 0x0F. Could there be something missing in
> > the ACPI hotplug code that overlooks this and removes the device on resume?
>
> That is possible. Actually even quite likely, but let's wait for the response
> from Peter.
Here's a hack that should take the 0xa return value into consideration. It
turned out that this case is even mentioned in the ACPI spec.
diff --git a/drivers/pci/hotplug/acpiphp_glue.c
b/drivers/pci/hotplug/acpiphp_glue.c
index e2a783fdb98f..014381b42d86 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -730,6 +730,17 @@ static unsigned int get_slot_status(struct acpiphp_slot
*slot)
return (unsigned int)sta;
}
+static inline bool device_sta_valid(unsigned long long sta)
+{
+ /*
+ * ACPI spec says that _STA may return bit 0 clear with bit 8 set
+ * if the device is valid but does not require device driver to be
+ * loaded (chapter 6.3.7).
+ */
+ unsigned mask = ACPI_STA_DEVICE_ENABLED | ACPI_STA_DEVICE_FUNCTIONING;
+ return (sta & mask) == mask;
+}
+
/**
* trim_stale_devices - remove PCI devices that are not responding.
* @dev: PCI device to start walking the hierarchy from.
@@ -745,7 +756,7 @@ static void trim_stale_devices(struct pci_dev *dev)
unsigned long long sta;
status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
- alive = (ACPI_SUCCESS(status) && sta == ACPI_STA_ALL)
+ alive = (ACPI_SUCCESS(status) && device_sta_valid(sta))
|| acpiphp_no_hotplug(handle);
}
if (!alive) {
@@ -792,7 +803,7 @@ static void acpiphp_check_bridge(struct acpiphp_bridge
*bridge)
mutex_lock(&slot->crit_sect);
if (slot_no_hotplug(slot)) {
; /* do nothing */
- } else if (get_slot_status(slot) == ACPI_STA_ALL) {
+ } else if (device_sta_valid(get_slot_status(slot))) {
/* remove stale devices if any */
list_for_each_entry_safe_reverse(dev, tmp,
&bus->devices,
bus_list)
--
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