Problems with devices that use PCI shared memory on 2nd PCI bus (6 slot powermac)

[Benjamin Herrenschmidt]

On Wed, 2007-01-10 at 15:05 +0000, Bob Brose wrote:
> Since Ben fixed the irq routing on 32 bit powermacs with changes to pci_32.c
> and prom_parse.c I've been able to use all 6 slots with interrupt
> driven devices however there appears to be a problem with devices that use
> memory mapping. (this is on a S900 w/ 21052 second PCI controller)
> 
> A couple of examples:
> When using a 21143 tulip ethernet card on the second PCI bus and with the 
> "Use PCI shared mem for NIC registers" option turned on the driver
> fails with incorrect status register reads. If I compile a kernel without
> this option it works fine.
> 
> Also, if I put a rage 128 video board in one of the slots on the
> second bus it cannot do DRM. If I turn DRM off it works ok or if I move the
> card to the first bus it works fine with DRM.

In lspci -vv, do you see the BusMaster bit enabled on the PCI-2-PCI
bridge ?

Ben.