From: Josh Triplett <josh@joshtriplett.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ben Hutchings <ben@decadent.org.uk>,
x86@kernel.org, 584846@bugs.debian.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: Bug#584846: Detects only 64MB and fails to boot on Intel Green City board if e820 hooked by GRUB2
Date: Sat, 12 Jun 2010 14:45:22 -0700 [thread overview]
Message-ID: <20100612214522.GA4994@feather> (raw)
In-Reply-To: <4C13F102.7000509@zytor.com>
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
next prev parent reply other threads:[~2010-06-12 21:46 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100612060322.29053.94187.reportbug@feather>
2010-06-12 13:58 ` Bug#584846: Detects only 64MB and fails to boot on Intel Green City board if e820 hooked by GRUB2 Ben Hutchings
2010-06-12 18:28 ` H. Peter Anvin
2010-06-12 18:55 ` Josh Triplett
2010-06-12 20:41 ` H. Peter Anvin
2010-06-12 21:45 ` Josh Triplett [this message]
[not found] ` <20100612222634.GA1785@feather>
2010-06-12 23:01 ` H. Peter Anvin
2010-06-12 23:02 ` H. Peter Anvin
2010-06-13 0:07 ` Josh Triplett
2010-06-13 0:16 ` H. Peter Anvin
[not found] ` <20100622052236.GA9130@feather>
2010-06-22 6:07 ` H. Peter Anvin
2010-06-22 16:07 ` Josh Triplett
2010-06-24 7:27 ` Josh Triplett
2010-06-24 14:18 ` H. Peter Anvin
2010-06-24 19:01 ` Josh Triplett
2010-06-24 20:58 ` H. Peter Anvin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100612214522.GA4994@feather \
--to=josh@joshtriplett.org \
--cc=584846@bugs.debian.org \
--cc=ben@decadent.org.uk \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).