Re: port-amd64/42980: satalink DMA fails under amd64

[Julian Bourne <julian.bourne%gmail.com@localhost>]

I found this morning that the EINVAL is due
to boundary (8192) being less than size (65536).

I've forced the boundary up to the size, as an experiment - metacode:

(boundary > 0 ? MAX(boundary, size) : boundary)

and now satalink DMA works.  That correction was made to
pciide_common.c on line 597 where the
call uses the constant MAXPHYS (65536) for the
size of the allocation.

But it looks to me like the root cause is actually
here in satalink.c (line 480):

        /*
         * Rev. <= 0x01 of the 3112 have a bug that can cause data
         * corruption if DMA transfers cross an 8K boundary.  This is
         * apparently hard to tickle, but we'll go ahead and play it
         * safe.
         */
        if (PCI_REVISION(pa->pa_class) <= 0x01) {
                sc->sc_dma_maxsegsz = 8192;
                sc->sc_dma_boundary = 8192;
        }

Given that the 3512 uses the 3112 code, that's
probably not applicable; however, it would still
be good if 3112 DMA worked on AMDs - so what
should change to make that work?

Should pciide_common be using
sc_dma_maxsegsz instead of MAXPHYS?

Thanks,

Julian.