Re: Busmaster DMA broken in 2.4.18 on Alpha

[Ivan Kokshaysky]

On Mon, Mar 11, 2002 at 10:02:00AM -0500, Jay Estabrook wrote:
> There are ISA cards, regardless of what ISA bus machine they are
> plugged into, that are able to generate only something less than
> 32-bits worth of address.

Indeed, I missed that.

> Since ISA devices don't have pci_dev structures, there's (currently)
> no way to pass an ISA device-dependent DMA mask to the IOMMU routines.
> Perhaps there needs to be an addition to the API that would allow
> for this (pci_set_isa_device_dma_mask()) ???

Yes, it would be nice to have something like this.

Another workaround also seems to be possible - for ISA devices
use mask other than 0x00ffffff _only_ if we don't have working
IOMMU. This doesn't help to get older Miatas work with such
type of ISA cards though...

Ivan.