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From:   Kunkun Li <likunkun@bytedance.com>
To:     minyard@acm.org, openipmi-developer@lists.sourceforge.net
Cc:     linux-kernel@vger.kernel.org, Kunkun Li <likunkun@bytedance.com>
Subject: [PATCH] ipmi: ssif: Add msleep in multipart test
Date:   Tue, 26 Oct 2021 10:58:34 +0800
Message-Id: <20211026025834.82766-1-likunkun@bytedance.com>
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During multipart test, cmd(6,7,8) or cmd(6,7,7) will
be sent continuously.

The pressure test found some BMC systems cannot process
messages in time, resulting in read_response continues to receive
error messages from i2c.
Retry mechanism will takes 10s, and finally set not support
multipart transmit.

So, to work around this，add msleep after sending cmd 6 and
cmd 7 respectively. The problem did not appear again in
pressure test.

Signed-off-by: Kunkun Li <likunkun@bytedance.com>
---
 drivers/char/ipmi/ipmi_ssif.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 20d5af92966d..65841798fafe 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1453,6 +1453,7 @@ static int start_multipart_test(struct i2c_client *client,
 	ret = i2c_smbus_write_block_data(client,
 					 SSIF_IPMI_MULTI_PART_REQUEST_START,
 					 32, msg);
+	msleep(SSIF_MSG_MSEC);
 	if (ret) {
 		retry_cnt--;
 		if (retry_cnt > 0)
@@ -1467,6 +1468,7 @@ static int start_multipart_test(struct i2c_client *client,
 	ret = i2c_smbus_write_block_data(client,
 					 SSIF_IPMI_MULTI_PART_REQUEST_MIDDLE,
 					 32, msg + 32);
+	msleep(SSIF_MSG_MSEC);
 	if (ret) {
 		dev_err(&client->dev, "Could not write multi-part middle, though the BMC said it could handle it.  Just limit sends to one part.\n");
 		return ret;
-- 
2.11.0