[Bug 930447] Re: Unable to start Ubuntu 12.04 live CD with syslinux loader on Pentium M x86 Laptop due to bug in PAE kernel, initramfs or syslinux

[roland aus köln]

>as Debian also includes a pae flags check in the 686 kernel package

the pae flags check is in the x86 bootcode of the kernel and apparently
it depends on the bootloader if it`s being executed or not.

only grub2 seems to skips that code which does vga initialization, cpu-
checking and other steps like edd (
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/arch/x86/boot/edd.c?id=e479c8306f898fcdb9b36179071eae6338a17364
) , which makes all the work pretty pointless.

i wonder, why skipping that code is possible at all and nobody complains
(besides that silent complain of hpa)

for details, see
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/x86/boot/main.c (end of the file)
and
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/x86/boot/cpu.c
and
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/x86/boot/cpucheck.c

btw - thanks Dimitrijs for the positive response.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to syslinux in Ubuntu.
https://bugs.launchpad.net/bugs/930447

Title:
  Unable to start Ubuntu 12.04 live CD with syslinux loader on Pentium M
  x86 Laptop due to bug in PAE kernel, initramfs or syslinux

Status in “syslinux” package in Ubuntu:
  Confirmed
Status in Baltix GNU/Linux:
  Triaged

Bug description:
  Ubuntu 12.04 doesn't start from Desktop CD or USB with syslinux boot
  loader on Pentium M 1.6Ghz or faster Pentium M CPU - displays error
  message about missing PAE feature in CPU, but *the same* *Ubuntu
  12.04* Desktop CD/LiveUSB starts fine on *the same CPU* (and same PAE
  kernel) if GRUB boot loader is used, for example when WUBI or LiveUSB
  with GRUB boot loader, like Multisystem
  (http://liveusb.info/dotclear/index.php?pages/install ) is used!

  The error message is:
  "This kernel requires the following features not present on the CPU: pae.
  Unable to boot - please use a kernel appropriate for you CPU."

  THIS IS AN IMPORTANT REGRESSION! People are able to install and successfully use Ubuntu 12.04 on such pretty new hardware, like IBM Thinkpad T42 laptop with Pentium M 1700Mhz processor, but the bug in syslinux (or something related) forbids Ubuntu 12.04 installation.
  This bug is reproducible on lots of computers, there are several log files and /proc/cpuinfo file attached to this bugreport, AFAIK it's enough to reopen this bug.

  ---
  ApportVersion: 1.23-0ubuntu4
  Architecture: i386
  CurrentDmesg: Error: command ['sh', '-c', 'dmesg | comm -13 --nocheck-order /var/log/dmesg -'] failed with exit code 1: comm: /var/log/dmesg: Permission denied
  MachineType: IBM 2373PPU
  dmi.bios.date: 06/18/2007
  dmi.bios.vendor: IBM
  dmi.bios.version: 1RETDRWW (3.23 )
  dmi.board.name: 2373PPU
  dmi.board.vendor: IBM
  dmi.board.version: Not Available
  dmi.chassis.asset.tag: No Asset Information
  dmi.chassis.type: 10
  dmi.chassis.vendor: IBM
  dmi.chassis.version: Not Available
  dmi.modalias: dmi:bvnIBM:bvr1RETDRWW(3.23):bd06/18/2007:svnIBM:pn2373PPU:pvrThinkPadT42:rvnIBM:rn2373PPU:rvrNotAvailable:cvnIBM:ct10:cvrNotAvailable:
  dmi.product.name: 2373PPU
  dmi.product.version: ThinkPad T42
  dmi.sys.vendor: IBM

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/syslinux/+bug/930447/+subscriptions