linux-kernel - [PATCH AUTOSEL for 4.15 23/78] media: [RESEND] media: dvb-frontends: Add delay to Si2168 restart

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Message-ID: <20180308045525.7662-23-alexander.levin@microsoft.com>
Date:   Thu, 8 Mar 2018 04:56:11 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
CC:     Ron Economos <w6rz@...cast.net>,
        Mauro Carvalho Chehab <mchehab@...pensource.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.15 23/78] media: [RESEND] media: dvb-frontends:
 Add delay to Si2168 restart

From: Ron Economos <w6rz@...cast.net>

[ Upstream commit 380a6c86457573aa42d27ae11e025eb25941a0b7 ]

On faster CPUs a delay is required after the resume command and the restart command. Without the delay, the restart command often returns -EREMOTEIO and the Si2168 does not restart.

Note that this patch fixes the same issue as https://patchwork.linuxtv.org/patch/44304/, but I believe my udelay() fix addresses the actual problem.

Signed-off-by: Ron Economos <w6rz@...cast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...pensource.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/media/dvb-frontends/si2168.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/media/dvb-frontends/si2168.c b/drivers/media/dvb-frontends/si2168.c
index 41d9c513b7e8..539399dac551 100644
--- a/drivers/media/dvb-frontends/si2168.c
+++ b/drivers/media/dvb-frontends/si2168.c
@@ -14,6 +14,8 @@
  *    GNU General Public License for more details.
  */
 
+#include <linux/delay.h>
+
 #include "si2168_priv.h"
 
 static const struct dvb_frontend_ops si2168_ops;
@@ -435,6 +437,7 @@ static int si2168_init(struct dvb_frontend *fe)
 		if (ret)
 			goto err;
 
+		udelay(100);
 		memcpy(cmd.args, "\x85", 1);
 		cmd.wlen = 1;
 		cmd.rlen = 1;
-- 
2.14.1