From c96614eeab663646f57f67aa591e015abd8bd0ba Mon Sep 17 00:00:00 2001 From: Enguerrand de Ribaucourt Date: Thu, 23 Jun 2022 15:46:44 +0200 Subject: [PATCH 1/2] 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 Reviewed-by: Andrew Lunn Signed-off-by: Jakub Kicinski --- 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 e6ad3a494d32c..95ef507053a66 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); From 0e597e2affb90d6ea48df6890d882924acf71e19 Mon Sep 17 00:00:00 2001 From: Enguerrand de Ribaucourt Date: Thu, 23 Jun 2022 15:46:45 +0200 Subject: [PATCH 2/2] net: dp83822: disable rx error interrupt Some RX errors, notably when disconnecting the cable, increase the RCSR register. Once half full (0x7fff), an interrupt flood is generated. I measured ~3k/s interrupts even after the RX errors transfer was stopped. Since we don't read and clear the RCSR register, we should disable this interrupt. Fixes: 87461f7a58ab ("net: phy: DP83822 initial driver submission") Signed-off-by: Enguerrand de Ribaucourt Reviewed-by: Andrew Lunn Signed-off-by: Jakub Kicinski --- drivers/net/phy/dp83822.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/phy/dp83822.c b/drivers/net/phy/dp83822.c index 95ef507053a66..8549e0e356c9b 100644 --- a/drivers/net/phy/dp83822.c +++ b/drivers/net/phy/dp83822.c @@ -229,8 +229,7 @@ static int dp83822_config_intr(struct phy_device *phydev) if (misr_status < 0) return misr_status; - misr_status |= (DP83822_RX_ERR_HF_INT_EN | - DP83822_LINK_STAT_INT_EN | + misr_status |= (DP83822_LINK_STAT_INT_EN | DP83822_ENERGY_DET_INT_EN | DP83822_LINK_QUAL_INT_EN);