[tulip] !HELP mii-diag set force:permision denied

[ling_yue@china.com]

 Dear all,
i am on redhat6.2 kernel 2.2.19(upgraded),i use accton En1207fvf(with tx & fx)(eeprom[4] differ) network card,i changed the tulip.c(v0.91) a little to suit my card :)
it run well after compiling.
Now i want to force the media to 100basetx-hd.
I compile and use mii-diag(v2.00).it display the correct mii reg.
when i type(as root):(after insmod .. netconfig..ping..)
"./mii-diag -F 100baseTx-HD -D eth0"
I found :
SIOCSMIIREG on eth0 failed: PERMISSION DENID
WHo can tell me how to solve it?

since i am an engineer,i changed the driver(tulip) in 2.2 and 2.4
I want to know whether Donald Becker can adapt it?
thanks for your time
Regards    
    ling yue            ling_yue@china.com

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