Re: Problems with MSI-X on ia64

[Grant Grundler <grundler@parisc-linux.org>]

On Fri, Feb 17, 2006 at 12:46:05AM -0800, Chris Wedgwood wrote:
> On Thu, Feb 16, 2006 at 11:58:29PM -0800, Grant Grundler wrote:
> 
> > The root cause is the use of u32 to describe a PCI resource "start".
> > phys_addr needs to be "unsigned long". More details in Log entry
> > below.
> 
> That won't always suffice.
> 
> I have machines at work that will place some PCI resources above the
> 4GB boundary even when booting in '32-bit OS' mode (there is a BIOS
> option for this but no matter the setting some resources always end up
> above 4GB).  I've heard from others they've also been hit by this
> (with 64-bit kernels it's fine).  I guess it could be argued that it's
> a BIOS bug, I'm not entirely sure what to thing,  Windows seems to
> deal with it.

If the machine is suppose to support a 32-bit OS, then yeah, it's
a BIOS bug. It all depends on who defines the support matrix.

One way to support that behavior is use u64 in struct resource (ioport.h)
(NOT dma_addr_t) instead of "unsigned long".

The other way is to reassign "invalid" resources (above 4GB) with 
"valid" ones (below 4GB).  I suspect windows is doing this and
I'd rather see linux take this route as well if possible.

grant