This was fixed in upstream by commit 7d9e6c5afab6 ("net: stmmac: Integrate XGMAC into main driver flow") that is a new feature commit.

We found a race condition in the DMA init sequence that hits if the PHY already has link up during stmmac_hw_setup. Since the ring length was programmed after enabling the RX path, we might receive a packet before the correct ring length is programmed. When that happened we could not get reliable interrupts for DMA RX and the MTL complained about RX FIFO overrun.

Signed-off-by: Lars Persson larper@axis.com Cc: stable@vger.kernel.org # 4.14.x Cc: Giuseppe Cavallaro peppe.cavallaro@st.com Cc: Alexandre Torgue alexandre.torgue@st.com Cc: Jose Abreu joabreu@synopsys.com --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 4a9dbee6f054..f2429ec07b57 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -2536,9 +2536,6 @@ static int stmmac_hw_setup(struct net_device *dev, bool init_ptp) netdev_warn(priv->dev, "%s: failed debugFS registration\n", __func__); #endif - /* Start the ball rolling... */ - stmmac_start_all_dma(priv); - priv->tx_lpi_timer = STMMAC_DEFAULT_TWT_LS;

if ((priv->use_riwt) && (priv->hw->dma->rx_watchdog)) { @@ -2558,6 +2555,9 @@ static int stmmac_hw_setup(struct net_device *dev, bool init_ptp) priv->hw->dma->enable_tso(priv->ioaddr, 1, chan); }

+ /* Start the ball rolling... */ + stmmac_start_all_dma(priv); + return 0; }