[realtek] autosense to halfduplex
Fri Jan 11 14:54:02 2002
On Fri, 11 Jan 2002, Nikolai Vladychevski wrote:
> when I buy a realtek card, it is alaways configured to autosense the media,
> and when it autosenses a hub that can do full duplex it is set to it. I want
> it to autosense but always to enter half duplex mode, is this possible?
Select 10baseT or 100baseTx based on the partner's link
beat signal. The link should always be set to half duplex.
The link partners negotiate the highest common capability.
The communication takes place on the 10baseT link beat bits.
This is the only standards-conforming way to use full duplex on
If no common capability is negotiated, the link is not usable.
If autonegotiation does not complete (e.g. an pre-autonegotiation
link partner), the transceiver falls back to autosense.
Autonegotiation is described at
The answer you are looking for is to advertise only half duplex
capabilities. You can do this with
mii-diag eth0 -A 0x00A0
This advertises 10baseT-HD and 100baseTx-HD only.
I'll explain the (admittedly obscure) constant
0x0001 Ethernet (always set in the report)
Normally you could use a text name such as
mii-diag -A 100baseTx-FD
but I didn't put in text names for all of the possible combinations.
Hmmm, perhaps I could change the option parsing to support a
mii-diag -A 10baseT-HD,100baseTx-HD
Donald Becker email@example.com
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