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    SubjectRe: [PATCH 1/1] r8169: revert "read MAC address from EEPROM on init"
    Krzysztof Halasa <khc@pm.waw.pl> :
    [...]
    > Ahh, just PCI VPD.
    >
    > IMHO the above shouldn't hurt anyone, in theory. You only write to
    > VPD_ADDR, and to change actual VPD data (i.e., EEPROM), you need to
    > write to VPD_DATA.
    >
    > Anyone should be allowed to do that even for unknown PCI devices
    > without a problem.

    Theorically, yes.

    In practice I noticed rather different behaviors between a 8168b and
    a 8110s when I tried accessing the eeprom through plain old bitbang
    a few months ago (i.e. ok on the 8110, lots of zero on the 8168b).

    > > -static void rtl_init_mac_address(struct rtl8169_private *tp,
    >
    > > - if (!(cfg1 & VPD)) {
    > > - if (netif_msg_probe(tp))
    > > - dev_info(&pdev->dev, "VPD access disabled, enabling\n");
    > > - RTL_W8(Cfg9346, Cfg9346_Unlock);
    > > - RTL_W8(Config1, cfg1 | VPD);
    > > - RTL_W8(Cfg9346, Cfg9346_Lock);
    >
    > Now I wonder what do they say the above does exactly.
    > Unfortunately the docs don't seem to be public.

    Realtek's legal department has changed his mind :o(

    From what I had received beforehand:

    RTL8169: R/W Set to enable Vital Product Data. The VPD data is stored in
    93C46 or 93c56 from within offset 40h-7fh.

    RTL8168C: R (huh ?) Set to enable Vital Product Data. Always 1.

    [...]
    > > - if (netif_msg_probe(tp)) {
    > > - DECLARE_MAC_BUF(buf);
    > > -
    > > - dev_info(&pdev->dev, "MAC address found in EEPROM: %s\n",
    > > - print_mac(buf, mac));
    > > - }
    > > -
    > > - if (is_valid_ether_addr(mac))
    > > - rtl_rar_set(tp, mac);
    > > -}
    >
    > No RTL_W8(Config1, cfg1 | ~VPD) to disable (perhaps R/W) access?

    Apparently not. See above.

    > Though obviously first reading a good address from the EEPROM and then
    > erasing first 32 bits is a different story.

    Yes.

    > I wonder if changing the MAC address by hand works (using ifconfig, to
    > arbitrary address).

    It does. It can be quite sticky. That was the whole point of the
    patch.

    --
    Ueimor


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