Messages in this thread | | | Date | Thu, 01 May 2008 14:11:50 -0700 | From | "H. Peter Anvin" <> | Subject | Re: Why such a big difference in init-time PCI resource call-paths (x86 vs x86_64) ? |
| |
Yinghai Lu wrote: > On Thu, May 1, 2008 at 1:11 PM, Andi Kleen <andi@firstfloor.org> wrote: >> On Thu, May 01, 2008 at 11:16:31AM -0700, Jesse Barnes wrote: >> > On Wednesday, April 30, 2008 9:07 am TJ wrote: >> > > In preparation for writing a Windows-style PCI resource allocation >> > > strategy >> > > >> > > - use all e820 gaps for IOMEM resources; top-down allocation - >> > > >> > > and thus giving devices with large IOMEM requirements more chance of >> > > allocation in the 32-bit address space below 4GB (see bugzilla #10461), >> >> I tried that some time ago and it turned out that some systems have >> mappings in holes and don't boot anymore when you fill the holes too much. >> But that was only considering e820. if you do this it might work if you >> do it really like windows and consider all resources, including ACPI. > > wonder if using holes in MTRR AND e820 could help... >
Typically not, since the MTRRs won't tell you what is free address space and what is occupied by non-BAR I/O devices.
-hpa
| |