linux-kernel - [PATCH 6/6] ACPI: EC: Use fast path in acpi_ec

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Date:   Thu, 27 Feb 2020 23:24:14 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux ACPI <linux-acpi@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Drake <drake@...lessm.com>
Subject: [PATCH 6/6] ACPI: EC: Use fast path in acpi_ec_add() for DSDT boot EC

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

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@...el.com>
---
 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 4ed0c6155d3f..920a08c01ab6 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1614,7 +1614,8 @@ 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