On Fri, 28 Sep 2012, H. Peter Anvin wrote: > On 09/28/2012 10:37 AM, Peter Hurley wrote: > > An interesting side note: more recent revisions of this BIOS (rev. A11) > > report one less variable MTRR (so, IA32_MTRRCAP is writable?) > > > >>> However, the right way to fix that is to use the PAT interfaces, which > >>> doesn't have this drawback -- then MTRR cleanup becomes entirely > >>> superfluous and the problem goes away. > >> Do you mean disable MTRR totally here? > > > > Well, since PAT entries marked WC override all MTRR settings, whatever > > the BIOS set the variable MTRRs to becomes irrelevant, so not disabled > > but rather ignored. > > > > The whole point is that the display stuff should not use MTRR, but > rather use PAT to provide WC. Then we don't need to "clean up" the > BIOS-set MTRRs.
What about my trusty ThinkPad T43, and other ia32 boxes that either lack PAT support, or have it blacklisted? These are exactly the boxes that will _never_ get a BIOS fix if their MTRRs are screwed up... -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
