| Message ID | 20241122141256.764578-1-maxime.chevallier@bootlin.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: stmmac: dwmac-socfpga: Set RX watchdog interrupt as broken | expand |
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c index 248b30d7b864..16020b72dec8 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c @@ -487,6 +487,8 @@ static int socfpga_dwmac_probe(struct platform_device *pdev) plat_dat->select_pcs = socfpga_dwmac_select_pcs; plat_dat->has_gmac = true; + plat_dat->riwt_off = 1; + ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res); if (ret) return ret;
On DWMAC3 and later, there's a RX Watchdog interrupt that's used for interrupt coalescing. It's known to be buggy on some platforms, and dwmac-socfpga appears to be one of them. Changing the interrupt coalescing from ethtool doesn't appear to have any effect here. Without disabling RIWT (Received Interrupt Watchdog Timer, I believe...), we observe latencies while receiving traffic that amount to around ~0.4ms. This was discovered with NTP but can be easily reproduced with a simple ping. Without this patch : 64 bytes from 192.168.5.2: icmp_seq=1 ttl=64 time=0.657 ms With this patch : 64 bytes from 192.168.5.2: icmp_seq=1 ttl=64 time=0.254 ms Fixes: 801d233b7302 ("net: stmmac: Add SOCFPGA glue driver") Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com> --- drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 2 ++ 1 file changed, 2 insertions(+)