linux-kernel - [PATCH v2] media: si2168: increase cmd execution timeout value

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Message-Id: <20250331084437.3974648-1-christianshewitt@gmail.com>
Date: Mon, 31 Mar 2025 08:44:37 +0000
From: Christian Hewitt <christianshewitt@...il.com>
To: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Peter Rosin <peda@...ntia.se>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	Heiner Kallweit <hkallweit1@...il.com>,
	Wolfram Sang <wsa+renesas@...g-engineering.com>,
	linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] media: si2168: increase cmd execution timeout value

Testing with a MyGica T230C v2 USB device (0572:c68a) shows occasional
cmd timeouts that cause Tvheadend services to fail:

Jan 28 12:23:46.788180 LibreELEC kernel: si2168 1-0060: cmd execution took 0 ms
Jan 28 12:23:46.790799 LibreELEC kernel: si2168 1-0060: cmd execution took 0 ms
Jan 28 12:23:46.878158 LibreELEC kernel: si2168 1-0060: cmd execution took 80 ms
Jan 28 12:23:46.879158 LibreELEC kernel: si2168 1-0060: failed=-110
Jan 28 12:23:46.879908 LibreELEC kernel: si2168 1-0060: failed=-110
Jan 28 12:23:46.948234 LibreELEC kernel: si2168 1-0060: cmd execution took 60 ms
Jan 28 12:23:46.949121 LibreELEC kernel: si2168 1-0060: cmd execution took 0 ms
Jan 28 12:23:46.949940 LibreELEC kernel: si2168 1-0060: cmd execution took 10 ms
..
Jan 28 12:23:57.457216 LibreELEC tvheadend[3126]: subscription: 009B: service instance is bad, reason: No input detected
Jan 28 12:23:57.457392 LibreELEC tvheadend[3126]: linuxdvb: Silicon Labs Si2168 #0 : DVB-T #0 - stopping 778MHz in DVB-T Network
..
Jan 28 12:23:57.457584 LibreELEC tvheadend[3126]: subscription: 009B: No input source available for subscription "127.0.0.1 [ | Kodi Media Center ]" to channel "XXXXXXX"

The original timeout of 50ms was extended to 70ms in commit 551c33e729f6
("[media] Si2168: increase timeout to fix firmware loading") but testing
shows there are other demux commands that take longer. The largest value
observed from user reports/logs is 150ms so increase timeout to 200ms.

Signed-off-by: Christian Hewitt <christianshewitt@...il.com>
Reviewed-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
---
Changes from v1 [0]:
- Rename TIMEOUT to CMD_TIMEOUT and move below #include
- Add Wolfram's review tag

[0] https://patchwork.linuxtv.org/project/linux-media/patch/20250331075838.3444332-1-christianshewitt@gmail.com/

 drivers/media/dvb-frontends/si2168.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/media/dvb-frontends/si2168.c b/drivers/media/dvb-frontends/si2168.c
index d6b6b8bc7d4e..843f1e01318e 100644
--- a/drivers/media/dvb-frontends/si2168.c
+++ b/drivers/media/dvb-frontends/si2168.c
@@ -9,6 +9,8 @@
 
 #include "si2168_priv.h"
 
+#define CMD_TIMEOUT 200
+
 static const struct dvb_frontend_ops si2168_ops;
 
 static void cmd_init(struct si2168_cmd *cmd, const u8 *buf, int wlen, int rlen)
@@ -40,8 +42,7 @@ static int si2168_cmd_execute(struct i2c_client *client, struct si2168_cmd *cmd)
 
 	if (cmd->rlen) {
 		/* wait cmd execution terminate */
-		#define TIMEOUT 70
-		timeout = jiffies + msecs_to_jiffies(TIMEOUT);
+		timeout = jiffies + msecs_to_jiffies(CMD_TIMEOUT);
 		while (!time_after(jiffies, timeout)) {
 			ret = i2c_master_recv(client, cmd->args, cmd->rlen);
 			if (ret < 0) {
@@ -58,7 +59,7 @@ static int si2168_cmd_execute(struct i2c_client *client, struct si2168_cmd *cmd)
 
 		dev_dbg(&client->dev, "cmd execution took %d ms\n",
 				jiffies_to_msecs(jiffies) -
-				(jiffies_to_msecs(timeout) - TIMEOUT));
+				(jiffies_to_msecs(timeout) - CMD_TIMEOUT));
 
 		/* error bit set? */
 		if ((cmd->args[0] >> 6) & 0x01) {
-- 
2.34.1