[patch 08/10] r8169: reduce max MTU for large frames

[akpm@xxxxxxxx]

From: Francois Romieu <romieu@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

 25-akpm/drivers/net/r8169.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff -puN drivers/net/r8169.c~r8169-reduce-max-mtu-for-large-frames 
drivers/net/r8169.c
--- 25/drivers/net/r8169.c~r8169-reduce-max-mtu-for-large-frames        
2005-01-04 21:57:36.322612408 -0800
+++ 25-akpm/drivers/net/r8169.c 2005-01-04 21:57:44.698339104 -0800
@@ -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                0x1c20  /* ... actually life sucks beyond ~7k */
 #define InterFrameGap  0x03    /* 3 means InterFrameGap = the shortest one */
 
 #define R8169_REGS_SIZE                256
@@ -1593,7 +1594,7 @@ 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;
_