Commit 2ef33ee7 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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

 # [1]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 6091b263

drivers/acpi/scan.c

+21 −6
Original line number Diff line number Diff line
@@ -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)

CRA Git | Maintained and supported by SUSTech CRA and CCSE