[PATCH 2.6.10-rc2-netdev1 4/4] r8169: reduce max MTU for large frames
From: Francois Romieu <romieu@fr.zoreil.com>
Date: 2004-11-16 22:36:04
The device does not support the whole mtu range it claims. Experimenting with the Tx threshold and/or the PCI burst size does not seem to improve the behavior. Signed-off-by: Francois Romieu <romieu@fr.zoreil.com> diff -puN drivers/net/r8169.c~r8169-265 drivers/net/r8169.c
--- linux-2.6.10-rc2-mm1.orig/drivers/net/r8169.c~r8169-265 2004-11-16 22:26:06.000000000 +0100
+++ linux-2.6.10-rc2-mm1/drivers/net/r8169.c 2004-11-16 22:26:06.000000000 +0100@@ -112,7 +112,8 @@ static int multicast_filter_limit = 32; #define RX_DMA_BURST 6 /* Maximum PCI burst, '6' is 1024 */ #define TX_DMA_BURST 6 /* Maximum PCI burst, '6' is 1024 */ #define EarlyTxThld 0x3F /* 0x3F means NO early transmit */ -#define RxPacketMaxSize 0x3FE8 /* 16K - 1 - ETH_HLEN - VLAN - CRC */ +#define RxPacketMaxSize 0x3FE8 /* 16K - 1 - ETH_HLEN - VLAN - CRC... */ +#define SafeMtu 0x1964 /* ... actually life sucks beyond ~7k */ #define InterFrameGap 0x03 /* 3 means InterFrameGap = the shortest one */ #define R8169_REGS_SIZE 256
@@ -1592,9 +1593,9 @@ static int rtl8169_change_mtu(struct net struct rtl8169_private *tp = netdev_priv(dev); int ret = 0; - if (new_mtu < ETH_ZLEN || new_mtu > RxPacketMaxSize) + if (new_mtu < ETH_ZLEN || new_mtu > SafeMtu) return -EINVAL; - + dev->mtu = new_mtu; if (!netif_running(dev))
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