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From:   Breno Leitao <leitao@debian.org>
To:     leitao@debian.org, kuba@kernel.org, netdev@vger.kernel.org
Cc:     leit@fb.com, davem@davemloft.net, edumazet@google.com,
        pabeni@redhat.com, sa+renesas@sang-engineering.com,
        linux-kernel@vger.kernel.org,
        Michael van der Westhuizen <rmikey@meta.com>
Subject: [PATCH] netpoll: Remove 4s sleep during carrier detection
Date:   Thu, 19 Jan 2023 08:44:48 -0800
Message-Id: <20230119164448.1348272-1-leitao@debian.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

This patch proposes to remove the msleep(4s) during netpoll_setup() if
the carrier appears instantly.

Modern NICs do not seem to have this bouncing problem anymore, and this
sleep slows down the machine boot unnecessarily

Reported-by: Michael van der Westhuizen <rmikey@meta.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 net/core/netpoll.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 9be762e1d042..6f45aeaf3da0 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -704,15 +704,6 @@ int netpoll_setup(struct netpoll *np)
 			msleep(1);
 		}
 
-		/* If carrier appears to come up instantly, we don't
-		 * trust it and pause so that we don't pump all our
-		 * queued console messages into the bitbucket.
-		 */
-
-		if (time_before(jiffies, atleast)) {
-			np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n");
-			msleep(4000);
-		}
 		rtnl_lock();
 	}
 
-- 
2.30.2