From da6b39a0db2e7e25affebc10cdd72c680c50d64f Mon Sep 17 00:00:00 2001
From: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@savoirfairelinux.com>
Date: Thu, 23 Jun 2022 15:46:44 +0200
Subject: [PATCH 28/32] net: dp83822: disable false carrier interrupt
Git-commit: c96614eeab663646f57f67aa591e015abd8bd0ba
References: git-fixes
Patch-mainline: v5.19-rc5

When unplugging an Ethernet cable, false carrier events were produced by
the PHY at a very high rate. Once the false carrier counter full, an
interrupt was triggered every few clock cycles until the cable was
replugged. This resulted in approximately 10k/s interrupts.

Since the false carrier counter (FCSCR) is never used, we can safely
disable this interrupt.

In addition to improving performance, this also solved MDIO read
timeouts I was randomly encountering with an i.MX8 fec MAC because of
the interrupt flood. The interrupt count and MDIO timeout fix were
tested on a v5.4.110 kernel.

Fixes: 87461f7a58ab ("net: phy: DP83822 initial driver submission")
Signed-off-by: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/phy/dp83822.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/net/phy/dp83822.c b/drivers/net/phy/dp83822.c
index ce17b2af3218..ab13699c20bc 100644
--- a/drivers/net/phy/dp83822.c
+++ b/drivers/net/phy/dp83822.c
@@ -229,7 +229,6 @@ static int dp83822_config_intr(struct phy_device *phydev)
 			return misr_status;
 
 		misr_status |= (DP83822_RX_ERR_HF_INT_EN |
-				DP83822_FALSE_CARRIER_HF_INT_EN |
 				DP83822_LINK_STAT_INT_EN |
 				DP83822_ENERGY_DET_INT_EN |
 				DP83822_LINK_QUAL_INT_EN);
-- 
2.16.4