[PATCH v2 5/6] ACPI: EC: Use fast path in acpi_ec_add() for DSDT boot EC

From: Rafael J. Wysocki
Date: Wed Mar 04 2020 - 05:52:56 EST


From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>

If the boot EC comes from the DSDT, its ACPI handle is equal to the
handle of a device object with the PNP0C09 device ID. If that
device object is passed to acpi_ec_add(), it is not necessary to
allocate a new EC structure for it and parse it, because that has
been done already, so change the function to use the fast path in
that case.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---

-> v2: Reorder (previously [6/6]) and rebase.

---
drivers/acpi/ec.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 116163add41b..355d6973cb70 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1611,7 +1611,8 @@ static int acpi_ec_add(struct acpi_device *device)
strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_EC_CLASS);

- if (!strcmp(acpi_device_hid(device), ACPI_ECDT_HID)) {
+ if ((boot_ec && boot_ec->handle == device->handle) ||
+ !strcmp(acpi_device_hid(device), ACPI_ECDT_HID)) {
/* Fast path: this device corresponds to the boot EC. */
ec = boot_ec;
} else {
--
2.16.4