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    SubjectRe: forcedeth: MAC-address reversed on resume from suspend
    [ original bug report: http://lkml.org/lkml/2008/1/2/253 ]

    On Wed, Jan 02, 2008 at 10:48:43PM +0100, Andreas Mohr wrote:
    > Hi,
    >
    > On Wed, Jan 02, 2008 at 10:04:49PM +0100, Richard Jonsson wrote:
    > > Bugreport regarding forcedeth driver.
    > >
    > > When returning from suspend-to-RAM the MAC-address byteorder is reversed.
    > > After another suspend-resume cycle the MAC-address is again correct. This
    > > brings a great deal of pain since the NIC is assigned a random MAC-address
    > > when it is detected as invalid.
    > >
    > > I cannot say if this issue appeared recently or if it's been in the kernel
    > > for a while, as I've been using wireless until recently.
    > >
    > > I read somewhere on lkml that the mac is read from the device, then
    > > reversed and finally written back to the device. Can it be that it is read
    > > again on resume and reversed, and then again written to the device? This
    > > would explain why it's ok every other resume cycle.
    >
    > Uh, Use The Source, Luke?
    >
    > But no, I think it's simply driver dainbreadness, not a matter of
    > complicated writing and reading back in reversed order.
    >
    > drivers/net/forcedeth.c has a nice DEV_HAS_CORRECT_MACADDR flag which is
    > being enabled for certain cards (those which need this) and disabled for others.
    >
    > The nv_probe() function then nicely obeys this flag by reversing the
    > address if needed, _however_ there's another function, nv_copy_mac_to_hw(),
    > which does _NOT_ obey it and simply copies the _raw_ netdev dev_addr
    > to the card register (NvRegMacAddrA etc.).
    >
    > I don't know, this all looks a bit dirty to me, MAC reading/writing
    > should have been implemented in a more central way, then those people
    > wouldn't have confused heaven and hell with MAC address fiddling.
    >
    > And yeah, this certainly looks like a bug that should be fixed ASAP,
    > unless my short analysis somehow happened to be wrong.
    > (I could probably fix it, but then the forcedeth people
    > most likely know better how they would like to see it implemented)
    >
    > Thank you for your report!
    >
    > Now the only thing remaining would be: is there a specific way to
    > contact forcedeth-related people? I didn't find anything within a short
    > search.

    Cc's added.

    > Andreas Mohr

    cu
    Adrian

    --

    "Is there not promise of rain?" Ling Tan asked suddenly out
    of the darkness. There had been need of rain for many days.
    "Only a promise," Lao Er said.
    Pearl S. Buck - Dragon Seed



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