how to PCI-passthrough 1 card to a DomU when another @ Dom0 uses the same driver?

["dev001" <pgngw+dev001+xen-users@f-m.fm>]

it was suggested (thx!) @ my OP
(http://lists.xensource.com/archives/html/xen-users/2011-02/msg00013.html)
might be more appropriate here ... hope that's the case (?)

my Dom0 host runs,

uname -a
        Linux test 2.6.34.8-7-xen #1 SMP 2011-01-20 21:58:39 +0100
        x86_64 x86_64 x86_64 GNU/Linux
lsb_release -d
        Description:    openSUSE 11.3 (x86_64)
rpm -qa | grep -i Xen-4
        xen-4.0.1_21326_02-0.3.1.x86_64

i've got 3 NICs,

lspci | grep -i eth
        02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
        RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 01)
        03:00.0 Ethernet controller: Marvell Technology Group Ltd.
        88E8053 PCI-E Gigabit Ethernet Controller (rev 20)
        04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
        RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 02)

where 04:00.0 is assigned as the internal-LAN/Bridge port, and 02:00.0 &
03:00.0 are PCIe cards that I intend to PCI-passthrough to a DomU guest.

so far, I've:

cat /boot/grub/menu.lst
        ...
    kernel /xen.gz ... iommu=verbose dom0_vcpus_pin=true sched=credit
    cpuidle=1 cpufreq=xen clocksource=acpi numa=on
    module /vmlinuz-xen ... elevator=cfq clocksource=xen mce=off
    nomodeset pciback.permissive
    pciback.hide=(0000:02:00.0)(0000:03:00.0)
    pci=resource_aligment=0000:02:00.0;0000:03:0.0
    module /initrd-xen
        ...

cat /etc/modprobe.d/99-local.conf
        options pciback hide=(0000:02:00.0)(0000:03:00.0)
        install sky2       /sbin/modprobe pciback ; /sbin/modprobe
        --first-time --ignore-install sky2
        install r8169      /sbin/modprobe pciback ; /sbin/modprobe
        --first-time --ignore-install r8169

cat /etc/init.d/boot.local
        modprobe pciback hide='(02:00.0)(03.00.0)'
        echo -n 0000:02:00.0 > sys/bus/pci/drivers/pciback/permissive
        echo -n 0000:03:00.0 > sys/bus/pci/drivers/pciback/permissive

@ Dom0 boot, i only see ONE card seized,

dmesg | egrep -i seiz
        [    2.081944] pciback 0000:03:00.0: seizing device

and, of course as a result, for a guest,

cat test.cfg
        ...
        extra = 'textmode=1 xencons=xvc0 elevator=noop iommu=soft'
        pci   = [ '02:00.0', '03:00.0']
        ...

xm create test.cfg
        Error: pci: PCI Backend and pci-stub don't own device
        0000:02:00.0


if i simply replace the 04:00.0 Realtek card with a non-r8619 driver
card, e.g.,

        04:00.0 Ethernet controller: Atheros Communications
        AR8121/AR8113/AR8114 Gigabit or Fast Ethernet (rev b0)

and repeat the experiment, then both cards are CORRECTLY seized,

dmesg | egrep -i seiz
        [    3.027654] pciback 0000:02:00.0: seizing device
        [    3.321515] pciback 0000:03:00.0: seizing device

and I can subsequently launch the DomU, with both cards successfully
passed through.

i.e., using two cards with the same driver type FAILS to allow one of
the cards to be seized.

i suspect this has to do with the driver not being unloadable at the
time of device seizure, as it's in use.

if that's the case -- how do i configure this so that the _same_ driver
can be used for _both_ the Dom0 card instance, and then appropriately
seized for the PCI-passthru target'd 2nd card?

or, is this another issue & there's addition/other config necessary?