Hi,
On 12/5/20 4:29 PM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> 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 in 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: Rafael J. Wysocki <[email protected]>
Thank you for doing this, I contemplated doing the exact same
thing but never got around to it.
One small review remark inline:
> ---
> drivers/acpi/scan.c | 27 +++++++++++++++++++++------
> 1 file changed, 21 insertions(+), 6 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -719,25 +719,40 @@ int acpi_device_add(struct acpi_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 */
I think this one can be dropped now, I checked my acpidump / dsdt.dsl
collection and 45/45 DSDTs declaring a _HID of INT3396 also added a _CID of
PNP0D80 to this.
Regards,
Hans
> + "PNP0D80", /* Windows-compatible System Power Management Controller */
> NULL
> };
>
> @@ -1857,7 +1872,7 @@ static void acpi_device_dep_initialize(s
> 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)
>
>
>
