Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
From:   Armin Wolf <W_Armin@gmx.de>
To:     pali@kernel.org
Cc:     jdelvare@suse.com, linux@roeck-us.net, linux-hwmon@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 3/3] hwmon: (dell-smm) Warn if SMM call took a very long time to execute
Date:   Tue, 26 Apr 2022 22:03:20 +0200
Message-Id: <20220426200320.399435-4-W_Armin@gmx.de>
In-Reply-To: <20220426200320.399435-1-W_Armin@gmx.de>
References: <20220426200320.399435-1-W_Armin@gmx.de>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

If a particular SMM call takes a very long time to execute,
the user might experience audio problems. Print a warning
if a particular SMM call took over 0.250 seconds to execute,
so the user can check whether or not possible audio problems
are caused by this driver.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
=2D--
 drivers/hwmon/dell-smm-hwmon.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon=
.c
index f13902414615..b960330eaded 100644
=2D-- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -49,6 +49,9 @@
 #define I8K_SMM_GET_DELL_SIG1	0xfea3
 #define I8K_SMM_GET_DELL_SIG2	0xffa3

+/* in usecs */
+#define DELL_SMM_MAX_DURATION  250000
+
 #define I8K_FAN_MULT		30
 #define I8K_FAN_RPM_THRESHOLD	1000
 #define I8K_MAX_TEMP		127
@@ -239,6 +242,9 @@ static int i8k_smm_func(void *par)
 	pr_debug("smm(0x%.4x 0x%.4x) =3D 0x%.4x  (took %7lld usecs)\n", eax, ebx=
,
 		 (rc ? 0xffff : regs->eax & 0xffff), duration);

+	if (duration > DELL_SMM_MAX_DURATION)
+		pr_warn("SMM call took %lld usecs!\n", duration);
+
 	return rc;
 }

=2D-
2.30.2