ACPI: scan: Add PNP0D80 to the _DEP exceptions list

The PNP0D80 ("Windows-compatible System Power Management Controller")
device ID is used for identifying the special device object providing
the LPI (Low-power S0 Idle) _DSM interface [1].  That device object
does not supply any operation regions, but it appears in _DEP lists
for other devices in the ACPI tables on some systems to enforce
specific enumeration ordering that does not matter for Linux.

For this reason, _DEP list entries pointing to the device object whose
_CID returns PNP0D80 need not be taken into account as real operation
region dependencies, so add that device ID to the list of device IDs
for which the matching _DEP list entries should be ignored.

Accordingly, update the function used for matching device IDs in that
list to allow it to check _CID as well as _HID and rename it to
acpi_info_matches_ids().

Link: https://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 25a46ae24229555897dfef4dabd370721da508e2..b44b2d6b6b2204d1c9ee28662d7c1e0f1a487761 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -719,25 +719,40 @@ int acpi_device_add(struct acpi_device *device,
 /* --------------------------------------------------------------------------
                                  Device Enumeration
    -------------------------------------------------------------------------- */
-static bool acpi_info_matches_hids(struct acpi_device_info *info,
-                                  const char * const hids[])
+static bool acpi_info_matches_ids(struct acpi_device_info *info,
+                                 const char * const ids[])
 {
+       struct acpi_pnp_device_id_list *cid_list = NULL;
        int i;
 
        if (!(info->valid & ACPI_VALID_HID))
                return false;
 
-       for (i = 0; hids[i]; i++) {
-               if (!strcmp(info->hardware_id.string, hids[i]))
+       if (info->valid & ACPI_VALID_CID)
+               cid_list = &info->compatible_id_list;
+
+       for (i = 0; ids[i]; i++) {
+               int j;
+
+               if (!strcmp(info->hardware_id.string, ids[i]))
                        return true;
+
+               if (!cid_list)
+                       continue;
+
+               for (j = 0; j < cid_list->count; j++) {
+                       if (!strcmp(cid_list->ids[j].string, ids[i]))
+                               return true;
+               }
        }
 
        return false;
 }
 
 /* List of HIDs for which we ignore matching ACPI devices, when checking _DEP lists. */
-static const char * const acpi_ignore_dep_hids[] = {
+static const char * const acpi_ignore_dep_ids[] = {
        "INT3396", /* Windows System Power Management Controller */
+       "PNP0D80", /* Windows-compatible System Power Management Controller */
        NULL
 };
 
@@ -1857,7 +1872,7 @@ static void acpi_device_dep_initialize(struct acpi_device *adev)
                        continue;
                }
 
-               skip = acpi_info_matches_hids(info, acpi_ignore_dep_hids);
+               skip = acpi_info_matches_ids(info, acpi_ignore_dep_ids);
                kfree(info);
 
                if (skip)