From: Heiner Kallweit <hkallweit1@gmail.com>
Date: Sat, 30 Mar 2019 16:13:24 +0000 (+0100)
Subject: r8169: disable default rx interrupt coalescing on RTL8168
X-Git-Tag: v5.1-rc4~19^2~26
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=288ac524cf70a8e7ed851a61ed2a9744039dae8d;p=thirdparty%2Flinux.git

r8169: disable default rx interrupt coalescing on RTL8168

It was reported that re-introducing ASPM, in combination with RX
interrupt coalescing, results in significantly increased packet
latency, see [0]. Disabling ASPM or RX interrupt coalescing fixes
the issue. Therefore change the driver's default to disable RX
interrupt coalescing. Users still have the option to enable RX
coalescing via ethtool.

[0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=925496

Fixes: a99790bf5c7f ("r8169: Reinstate ASPM Support")
Reported-by: Mike Crowe <mac@mcrowe.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 7562ccbbb39af..19efa88f3f02d 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -5460,7 +5460,7 @@ static void rtl_hw_start_8168(struct rtl8169_private *tp)
 	tp->cp_cmd |= PktCntrDisable | INTT_1;
 	RTL_W16(tp, CPlusCmd, tp->cp_cmd);
 
-	RTL_W16(tp, IntrMitigate, 0x5151);
+	RTL_W16(tp, IntrMitigate, 0x5100);
 
 	/* Work around for RxFIFO overflow. */
 	if (tp->mac_version == RTL_GIGA_MAC_VER_11) {