On Wed, May 19, 2010 at 11:43:00AM +0200, Christoph Egger wrote: > The following memory types exist: > > - Uncacheable > - Write-Combining > - Write-Protect > - Write-Through > - Writeback > - Uncacheable Minus IIUC, the memory type set by PAT applies at VA -> PA mapping. Can't one physical page be mapped at two VAs with conflicting memory types? On one physical range, can PAT and MTRR simultaneously set conflicting memory types? Can we detect/avoid the conflict? Are some memory types more suitable for a DMA buffer than others? Where PAT is not available, can't we fall back to using a facility such as MTRR to set memory types? Dave -- David Young OJC Technologies dyoung%ojctech.com@localhost Urbana, IL * (217) 278-3933