[PATCH 5.4 006/108] net: dp83822: disable false carrier interrupt

[Greg Kroah-Hartman]

From: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@xxxxxxxxxxxxxxxxxxxx>

commit c96614eeab663646f57f67aa591e015abd8bd0ba upstream.

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@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/phy/dp83822.c |    1 -
 1 file changed, 1 deletion(-)

--- a/drivers/net/phy/dp83822.c
+++ b/drivers/net/phy/dp83822.c
@@ -198,7 +198,6 @@ static int dp83822_config_intr(struct ph
 			return misr_status;
 
 		misr_status |= (DP83822_RX_ERR_HF_INT_EN |
-				DP83822_FALSE_CARRIER_HF_INT_EN |
 				DP83822_ANEG_COMPLETE_INT_EN |
 				DP83822_DUP_MODE_CHANGE_INT_EN |
 				DP83822_SPEED_CHANGED_INT_EN |