Forcing Full-Duplex on Realtek card

Sascha Holzleiter mlists+freebsd-net at daemonground.de
Wed Dec 15 17:51:12 UTC 2010


Hello,

i just discovered it seems to be impossible to force a duplex setting if the 
switchport is not doing autonegotiation. 
The server in question has a Realtek 1GBit device but the hosting company
reduces the speed on their switches to 100MBit. So after booting without
any options this gives me:

re0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
	
options=389b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_UCAST,WOL_MCAST,WOL_MAGIC>
	ether XX:XX:XX:XX:XX:XX
	inet 46.X.X.X netmask 0xffffffc0 broadcast 46.X.X.X
	media: Ethernet 100baseTX <half-duplex>
	status: active

I though this wasn't a big deal and tried to force it to full-duplex:

# ifconfig re0 media 100baseTX mediaopt full-duplex

but it seems the actual setting is still half-duplex:

re0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
	
options=389b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_UCAST,WOL_MCAST,WOL_MAGIC>
	ether XX:XX:XX:XX:XX:XX
	inet 46.X.X.X netmask 0xffffffc0 broadcast 46.X.X.X
	media: Ethernet 100baseTX <full-duplex> (100baseTX <half-duplex>)
	status: active

This is on a FreeBSD 8.1-RELEASE amd64 system and the hardware in questions 
is:

re0 at pci0:6:0:0:	class=0x020000 card=0x75221462 chip=0x816810ec rev=0x02 
hdr=0x00
    vendor     = 'Realtek Semiconductor'
    device     = 'Gigabit Ethernet NIC(NDIS 6.0) (RTL8168/8111/8111c)'
    class      = network
    subclass   = ethernet

Is there anything i can do to force the full-duplex setting for good?


Regards,
  Sascha


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