On Friday 18 January 2008 07:28:49 pm Dave Jones wrote: > On Fri, Jan 18, 2008 at 10:02:10PM +0100, Ingo Molnar wrote: > > > > * Dave Jones <[EMAIL PROTECTED]> wrote: > > > > > > you mean modifies MTRRs? Which code is that? (besides the > > > > /proc/mtrr userspace API) > > > > > > This exclusion is going to be a real pain in the ass for distro > > > kernels. It's impossible for example to build a kernel that will now > > > support the MTRR-alike registers on the AMD K6/early Cyrix etc and > > > also support PAT. > > > > > > Additionally, given people tend to update their kernels a lot more > > > often than they update to a whole new version of X, it means until > > > userspace has caught up, we can't ship a kernel with PAT supported, or > > > else X gets a lot slower due to the missing mtrr support. > > > > there's no exclusion enforced right now, and if a CPU is PAT-incapable > > (or if the kernel is booted nopat) then the MTRR bits should be usable. > > But if we boot with PAT enabled, and Xorg gets /proc/mtrr wrong, we'll > > see nasty crashes. If it gets them right, it should all still work just > > fine. Is this ok? Then, in a year or two, distros can disable write > > support to /proc/mtrr. Hm? > > A crazy idea just occured to me.. We could make /proc/mtrr an interface > to set PAT on a range of memory. This would make it transparently work > without any changes in X or anything else that sets them in userspace.
goog idea... we need to make X86_PAT depend on MTRR in arch/x86/Kconfig YH -- 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/
