[lkml]   [2010]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: Bug#584846: Detects only 64MB and fails to boot on Intel Green City board if e820 hooked by GRUB2
    On Sat, Jun 12, 2010 at 01:41:38PM -0700, H. Peter Anvin wrote:
    > On 06/12/2010 11:55 AM, Josh Triplett wrote:
    > >>
    > >> It's kind of hard to know what is involved, since clearly it relates to
    > >> Grub2, which -- how do I say this politely -- seems to excel at doing
    > >> things in the most inferior way possible. This is a great example of that.
    > >>
    > >> The most likely reason it fails is because Grub2 uses ACPI 3-style reads
    > >> of the board memory map, gets wrong results for the same reasons the
    > >> kernel do, and then pass then downstream to the kernel. As such, there
    > >> is absolutely nothing the kernel can do about it.
    > >
    > > grub2 doesn't do ACPI 3 reads; it always asks for 20 bytes, not 24.
    > >
    > > Also, note that it works with older Linux kernels (before the commit in
    > > question) and fails with newer ones. That doesn't rule out the
    > > possibility of a grub bug instead of a Linux bug, but since older Linux
    > > somehow coped with the situation, it seems like a regression that newer
    > > Linux cannot cope.
    > >
    > It's a regression of sorts, sure; but the new Linux code also boots on
    > real hardware which it didn't boot before. Since this requires Grub2
    > plus specific hardware, it is hard for me to track down what the problem
    > might be, but a good step on the way might be to use the Grub2 boot
    > procedure (with the drive remapping) to chainboot Syslinux, and run
    > meminfo.c32 which is a memory report debugging tool; it might be able to
    > give some answers at least.

    Will do.

    - Josh Triplett

     \ /
      Last update: 2010-06-12 23:49    [W:0.022 / U:5.460 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site