>>> Why do you care about performance when PAT is disabled? breaking old boxes just because, is just going to get reverted when I get the first regression report that you broke old boxes. Andy Lutomirski just submitted a bunch of patches to clean up the DRM usage of mtrrs, they are in drm-next, afaik we no longer add them on PAT systems. Dave. >> >> It will regress already slow boxes. We blacklist a LOT of P4s, PMs, etc and >> nobody ever took the pain to track down which ones of those actually have >> PAT+MTRR aliasing bugs. >> >> These boxes have boards like the Radeon X300, which needs either PAT or MTRR >> to not become unusable... >> > > We're talking hardware which is now many years old, but this is causing > very serious problems on real, modern hardware. As far as I understand > it, too, the blacklisting was precautionary (the only bug that I > personally know about is a performance bug, where WC would be > incorrectly converted to UC.) > > We need a way forward here. If it is the only way I think we would have > to sacrifice the old machines, but perhaps something can be worked out > (e.g. if PAT is disabled, fall back to MTRRs if available for ioremap_wc()). > > -hpa > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
