The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c96614eeab663646f57f67aa591e015abd8bd0ba 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] net: dp83822: disable false carrier interrupt

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

diff --git a/drivers/net/phy/dp83822.c b/drivers/net/phy/dp83822.c index e6ad3a494d32..95ef507053a6 100644 --- a/drivers/net/phy/dp83822.c +++ b/drivers/net/phy/dp83822.c @@ -230,7 +230,6 @@ 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);