On Fri, Jun 01, 2007 at 02:41:57PM -0700, Jesse Barnes wrote: > On Friday, June 1, 2007 2:19:43 Andi Kleen wrote: > > And normally the MTRRs win, don't they (if I remember the table correctly) > > So if the MTRR says UC and PAT disagrees it might not actually help > > I just checked, yes the MTRRs win for UC types. But it sounds like the cases > we're talking about are actually situations where there's no MTRR coverage, > so the default type is used. The manual doesn't specifically call out how > memory using the default type interacts with PAT, but it may well be that it > stays uncached if the default type is uncached. Again that argues for fixing > the MTRR mapping problem in some way. > I feel, having a silent/transparent workaround is not a good idea. With that chances are BIOS bug will go unnoticed (having an error message in dmesg may not get noticed either). Probably we should just panic at boot with a detailed message about the e820 mtrr discrepancy (which can be logged as a BUG to BIOS provider) and suggest a temporary workaround of "mem=___". Thanks, Venki - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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