From: Heiner Kallweit <hkallweit1@xxxxxxxxx> [ Upstream commit 21b5f672fb2eb1366dedc4ac9d32431146b378d3 ] It turned out that on low performance systems the original change can cause lower tx performance. On a N3450-based mini-PC tx performance in iperf3 was reduced from 950Mbps to ~900Mbps. Therefore effectively revert the original change, just use pcie_set_readrq() now instead of changing the PCIe capability register directly. Fixes: 2df49d365498 ("r8169: remove fiddling with the PCIe max read request size") Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/realtek/r8169_main.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -3865,15 +3865,18 @@ static void rtl_hw_jumbo_enable(struct r switch (tp->mac_version) { case RTL_GIGA_MAC_VER_12: case RTL_GIGA_MAC_VER_17: + pcie_set_readrq(tp->pci_dev, 512); r8168b_1_hw_jumbo_enable(tp); break; case RTL_GIGA_MAC_VER_18 ... RTL_GIGA_MAC_VER_26: + pcie_set_readrq(tp->pci_dev, 512); r8168c_hw_jumbo_enable(tp); break; case RTL_GIGA_MAC_VER_27 ... RTL_GIGA_MAC_VER_28: r8168dp_hw_jumbo_enable(tp); break; case RTL_GIGA_MAC_VER_31 ... RTL_GIGA_MAC_VER_33: + pcie_set_readrq(tp->pci_dev, 512); r8168e_hw_jumbo_enable(tp); break; default: @@ -3903,6 +3906,9 @@ static void rtl_hw_jumbo_disable(struct break; } rtl_lock_config_regs(tp); + + if (pci_is_pcie(tp->pci_dev) && tp->supports_gmii) + pcie_set_readrq(tp->pci_dev, 4096); } static void rtl_jumbo_config(struct rtl8169_private *tp, int mtu)