[E1000-devel] Loopback problem of 82571EB fiber interface

[tsai w. y. <wyt...@gm...>]

I am assigned a job to test the loopback functionality of the 82571EB
Copper / Fiber
interfaces. The spec requires, when the interface is loopbacked, the
directly connected
interface in the other side should show a link down state. I first try
to set the
MII_MR_LOOPBACK bit of the Copper interface card and see link state of
the directly
conneted interface is down. But when I try the same method for the
Fiber interface, it
seems not work. I replace the simple bit setting with the code snippet
(e1000_setup_loopback_test() & e1000_loopback_cleanup()) from
e1000_loopback_test():

int setDevLoopback(struct net_device *dev, int enable)
{
    ...
    if (enable)
    {
        switch(adapter->hw.mac_type)
        {
            case 82571:
            if (adapter->hw.media_type == e1000_media_type_fiber)
            {
                e1000_setup_loopback_test(adapter);
            }
            else
            {
                e1000_read_phy_reg(&adapter->hw, PHY_CTRL, &phy_reg);
	phy_reg |= MII_CR_LOOPBACK;
	e1000_write_phy_reg(&adapter->hw, PHY_CTRL, phy_reg);
            }
            break;
        }
    }
    else
    {
        switch(adapter->mac_type)
        {
            case 82571:
            if (adapter->hw.media_type == e1000_media_type_fiber)
            {
                e1000_loopback_cleanup(adapter);
                e1000_reset(adapter);
            }
            else
            {
                e1000_read_phy_reg(&adapter->hw, PHY_CTRL, &phy_reg);
	phy_reg &= ~MII_CR_LOOPBACK;
	e1000_write_phy_reg(&adapter->hw, PHY_CTRL, phy_reg);
            }
            break;
        }
}

After the Fiber interface is loopbacked, the link state of the
directly connected interface
is still up. But when I restart the auto-negotiation process of the
connected interfce, the
process fails, and the link falls to down.

Does anyone know how to down the connected interface's link when the
Fiber interface
is loopbacked ?

lspci info of the 82571 Fiber interfaces:

04:00.0 Ethernet controller: Intel Corporation 82571EB Gigabit
Ethernet Controller (rev 06)
        Subsystem: Intel Corporation PRO/1000 PF Dual Port Server Adapter
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66Mhz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 0, cache line size 10
        Interrupt: pin A routed to IRQ 5
        Region 0: Memory at fd8e0000 (32-bit, non-prefetchable) [size=128K]
        Region 1: Memory at fd8c0000 (32-bit, non-prefetchable) [size=128K]
        Region 2: I/O ports at 7f00 [size=32]
        Expansion ROM at <unassigned> [disabled] [size=128K]
        Capabilities: [c8] Power Management version 2
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA
PME(D0+,D1-,D2-,D3hot+,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=1 PME-
        Capabilities: [d0] Message Signalled Interrupts: 64bit+
Queue=0/0 Enable-
                Address: 0000000000000000  Data: 0000
        Capabilities: [e0] #10 [0001]

04:00.1 Ethernet controller: Intel Corporation 82571EB Gigabit
Ethernet Controller (rev 06)
        Subsystem: Intel Corporation PRO/1000 PF Dual Port Server Adapter
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66Mhz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 0, cache line size 10
        Interrupt: pin B routed to IRQ 9
        Region 0: Memory at fd8a0000 (32-bit, non-prefetchable) [size=128K]
        Region 1: Memory at fd880000 (32-bit, non-prefetchable) [size=128K]
        Region 2: I/O ports at 7e00 [size=32]
        Expansion ROM at <unassigned> [disabled] [size=128K]
        Capabilities: [c8] Power Management version 2
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA
PME(D0+,D1-,D2-,D3hot+,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=1 PME-
        Capabilities: [d0] Message Signalled Interrupts: 64bit+
Queue=0/0 Enable-
                Address: 0000000000000000  Data: 0000
        Capabilities: [e0] #10 [0001]


Regards, wenyen