queue-5.0/r8169-disable-default-rx-interrupt-coalescing-on-rtl.patch

   1 From d6cf7e8335a973f1338eb4949994c0c3ce6d9d34 Mon Sep 17 00:00:00 2001
   2 From: Heiner Kallweit <hkallweit1@gmail.com>
   3 Date: Sat, 30 Mar 2019 17:13:24 +0100
   4 Subject: r8169: disable default rx interrupt coalescing on RTL8168
   5
   6 [ Upstream commit 288ac524cf70a8e7ed851a61ed2a9744039dae8d ]
   7
   8 It was reported that re-introducing ASPM, in combination with RX
   9 interrupt coalescing, results in significantly increased packet
  10 latency, see [0]. Disabling ASPM or RX interrupt coalescing fixes
  11 the issue. Therefore change the driver's default to disable RX
  12 interrupt coalescing. Users still have the option to enable RX
  13 coalescing via ethtool.
  14
  15 [0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=925496
  16
  17 Fixes: a99790bf5c7f ("r8169: Reinstate ASPM Support")
  18 Reported-by: Mike Crowe <mac@mcrowe.com>
  19 Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
  20 Signed-off-by: David S. Miller <davem@davemloft.net>
  21 Signed-off-by: Sasha Levin <sashal@kernel.org>
  22 ---
  23  drivers/net/ethernet/realtek/r8169.c | 2 +-
  24  1 file changed, 1 insertion(+), 1 deletion(-)
  25
  26 diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
  27 index 5adb00f521db..365cddbfc684 100644
  28 --- a/drivers/net/ethernet/realtek/r8169.c
  29 +++ b/drivers/net/ethernet/realtek/r8169.c
  30 @@ -5333,7 +5333,7 @@ static void rtl_hw_start_8168(struct rtl8169_private *tp)
  31         tp->cp_cmd |= PktCntrDisable | INTT_1;
  32         RTL_W16(tp, CPlusCmd, tp->cp_cmd);
  33
  34 -       RTL_W16(tp, IntrMitigate, 0x5151);
  35 +       RTL_W16(tp, IntrMitigate, 0x5100);
  36
  37         /* Work around for RxFIFO overflow. */
  38         if (tp->mac_version == RTL_GIGA_MAC_VER_11) {
  39 --
  40 2.19.1
  41