[PATCH v3 4/4] platform/x86: ideapad-laptop: Evaluate ACPI methods exclusively

[Ali Ahmet Memiş]

On some Lenovo IdeaPad and Yoga models, the battery _BIX takes the EC
AML mutex and then calls the serialized RDER through RDIF, while GBMD
calls RDER first and then takes the EC mutex. When the two run
interleaved they deadlock until the mutex acquisition in RDER times
out, and GBMD returns garbage that is reported as both charge types
being enabled.

Evaluate all methods with the exclusive helpers, so that GBMD never runs
interleaved with the battery methods.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=221065
Link: https://lore.kernel.org/all/58586fa666f09c209f9d7fe8c692a8bdda6d4410.camel@xxxxxxxx/
Signed-off-by: Ali Ahmet Memiş <aliamemis@xxxxxxxxxxx>
Reviewed-by: Rong Zhang <i@xxxxxxxx>
---
 drivers/platform/x86/lenovo/ideapad-laptop.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/lenovo/ideapad-laptop.c b/drivers/platform/x86/lenovo/ideapad-laptop.c
index 8213524504ee..1335f4e48870 100644
--- a/drivers/platform/x86/lenovo/ideapad-laptop.c
+++ b/drivers/platform/x86/lenovo/ideapad-laptop.c
@@ -297,12 +297,16 @@ static void ideapad_shared_exit(struct ideapad_private *priv)
 #define IDEAPAD_EC_POLL_MIN_US 150
 #define IDEAPAD_EC_POLL_MAX_US 300
 
+/*
+ * On some models GBMD and the battery _BIX take the EC mutex and a
+ * serialized method in opposite order, so evaluate all methods exclusively.
+ */
 static int eval_int(acpi_handle handle, const char *name, unsigned long *res)
 {
 	unsigned long long result;
 	acpi_status status;
 
-	status = acpi_evaluate_integer(handle, (char *)name, NULL, &result);
+	status = acpi_evaluate_integer_exclusive(handle, (char *)name, NULL, &result);
 	if (ACPI_FAILURE(status))
 		return -EIO;
 
@@ -324,7 +328,7 @@ static int eval_int_with_arg(acpi_handle handle, const char *name, unsigned long
 	in_obj.type = ACPI_TYPE_INTEGER;
 	in_obj.integer.value = arg;
 
-	status = acpi_evaluate_integer(handle, (char *)name, &params, &result);
+	status = acpi_evaluate_integer_exclusive(handle, (char *)name, &params, &result);
 	if (ACPI_FAILURE(status))
 		return -EIO;
 
@@ -336,7 +340,7 @@ static int eval_int_with_arg(acpi_handle handle, const char *name, unsigned long
 
 static int exec_simple_method(acpi_handle handle, const char *name, unsigned long arg)
 {
-	acpi_status status = acpi_execute_simple_method(handle, (char *)name, arg);
+	acpi_status status = acpi_execute_simple_method_exclusive(handle, (char *)name, arg);
 
 	return ACPI_FAILURE(status) ? -EIO : 0;
 }
@@ -394,7 +398,7 @@ static int eval_vpcw(acpi_handle handle, unsigned long cmd, unsigned long data)
 	in_obj[1].type = ACPI_TYPE_INTEGER;
 	in_obj[1].integer.value = data;
 
-	status = acpi_evaluate_object(handle, "VPCW", &params, NULL);
+	status = acpi_evaluate_object_exclusive(handle, "VPCW", &params, NULL);
 	if (ACPI_FAILURE(status))
 		return -EIO;
 
-- 
2.55.0