linux-kernel - [PATCH v1 3/3] ACPI: EC: Evaluate _REG outside the EC scope more carefully

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Message-ID: <23612351.6Emhk5qWAg@rjwysocki.net>
Date: Mon, 12 Aug 2024 15:16:21 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux ACPI <linux-acpi@...r.kernel.org>
Cc: Hans de Goede <hdegoede@...hat.com>, LKML <linux-kernel@...r.kernel.org>,
 "Rafael J. Wysocki" <rafael@...nel.org>, Armin Wolf <w_armin@....de>
Subject:
 [PATCH v1 3/3] ACPI: EC: Evaluate _REG outside the EC scope more carefully

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

Commit 60fa6ae6e6d0 ("ACPI: EC: Install address space handler at the
namespace root") caused _REG methods for EC operation regions outside
the EC device scope to be evaluated which on some systems leads to the
evaluation of _REG methods in the scopes of device objects representing
devices that are not present and not functional according to the _STA
return values. Some of those device objects represent EC "alternatives"
and if _REG is evaluated for their operation regions, the platform
firmware may be confused and the platform may start to behave
incorrectly.

To avoid this problem, only evaluate _REG for EC operation regions
located in the scopes of device objects representing known-to-be-present
devices.

For this purpose, partially revert commit 60fa6ae6e6d0 and trigger the
evaluation of _REG for EC operation regions from acpi_bus_attach() for
the known-valid devices.

Fixes: 60fa6ae6e6d0 ("ACPI: EC: Install address space handler at the namespace root")
Link: https://lore.kernel.org/linux-acpi/1f76b7e2-1928-4598-8037-28a1785c2d13@redhat.com
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2298938
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2302253
Reported-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Reviewed-by: Hans de Goede <hdegoede@...hat.com>
---
 drivers/acpi/ec.c       |   11 +++++++++--
 drivers/acpi/internal.h |    1 +
 drivers/acpi/scan.c     |    2 ++
 3 files changed, 12 insertions(+), 2 deletions(-)

Index: linux-pm/drivers/acpi/ec.c
===================================================================
--- linux-pm.orig/drivers/acpi/ec.c
+++ linux-pm/drivers/acpi/ec.c
@@ -1530,12 +1530,13 @@ static bool install_gpio_irq_event_handl
 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
 			       bool call_reg)
 {
-	acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
 	acpi_status status;

 	acpi_ec_start(ec, false);

 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
+		acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
+
 		acpi_ec_enter_noirq(ec);
 		status = acpi_install_address_space_handler_no_reg(scope_handle,
 								   ACPI_ADR_SPACE_EC,
@@ -1549,7 +1550,7 @@ static int ec_install_handlers(struct ac
 	}

 	if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
-		acpi_execute_reg_methods(scope_handle, ACPI_UINT32_MAX, ACPI_ADR_SPACE_EC);
+		acpi_execute_reg_methods(ec->handle, ACPI_UINT32_MAX, ACPI_ADR_SPACE_EC);
 		set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
 	}

@@ -1764,6 +1765,12 @@ static void acpi_ec_remove(struct acpi_d
 	}
 }

+void acpi_ec_register_opregions(struct acpi_device *adev)
+{
+	if (first_ec && first_ec->handle != adev->handle)
+		acpi_execute_reg_methods(adev->handle, 1, ACPI_ADR_SPACE_EC);
+}
+
 static acpi_status
 ec_parse_io_ports(struct acpi_resource *resource, void *context)
 {
Index: linux-pm/drivers/acpi/internal.h
===================================================================
--- linux-pm.orig/drivers/acpi/internal.h
+++ linux-pm/drivers/acpi/internal.h
@@ -224,6 +224,7 @@ int acpi_ec_add_query_handler(struct acp
 			      acpi_handle handle, acpi_ec_query_func func,
 			      void *data);
 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
+void acpi_ec_register_opregions(struct acpi_device *adev);

 #ifdef CONFIG_PM_SLEEP
 void acpi_ec_flush_work(void);
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -2271,6 +2271,8 @@ static int acpi_bus_attach(struct acpi_d
 	if (device->handler)
 		goto ok;

+	acpi_ec_register_opregions(device);
+
 	if (!device->flags.initialized) {
 		device->flags.power_manageable =
 			device->power.states[ACPI_STATE_D0].flags.valid;