[CentOS] RTL8111/8168B always 100mbps

Tue Sep 27 03:15:18 UTC 2011
Muhammad Panji <sumodirjo at gmail.com>

Dear All,
I have an onboard Realtek RTL8111/8168B NIC. from lspci -vv :

02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 02)

It is detected, but why the speed is always 100Mbps, already change
cable but still no luck. I use ethtool and from the output it seems
that system know that this NIC support gigabit speed :


        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full

have change the driver r8169 with r8168 and follow the guide on CentOS
wiki http://wiki.centos.org/AdditionalResources/HardwareList/RealTekRTL8111b
but still it only get 100Mbps speed.

I user kernel 2.6.18-274.3.1.el5 and 2.6.18-274.3.1.el5-PAE. on
another machine with the same specs I use kernel  2.6.18-238.9.1.el5
and the gigabit speed works.

Any idea why this happened and how to solve it? Thank you.
Regards,





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Muhammad Panji
http://www.panji.web.id                         http://www.kurungsiku.com
http://sumodirjo.wordpress.com          http://www.kurungsiku.web.id

http://www.linuxbox.web.id