linux v2.4, initrd, 1 gig mem: LINUX_INITRD_MAX_ADDRESS too high

[Erik Schoenfelder]

Hi,

we had some trouble loading a initrd ramdisk with grub version
0.5.96.1 on a linux kernel version 2.4.1 (failed with 2.4.0 too; both
configured with CONFIG_HIGHMEM4G=y) on a asus cur-dls mainboard with
one gig of memory.

the ramdisk was reported to be behind end of mem and therefore
ignored.

this fix solved the trouble:

*** 138,144 ****
  #define LINUX_MAGIC_SIGNATURE         0x53726448      /* "HdrS" */
  #define LINUX_DEFAULT_SETUP_SECTS     4
  #define LINUX_FLAG_CAN_USE_HEAP               0x80
! #define LINUX_INITRD_MAX_ADDRESS      0x3C000000
  #define LINUX_MAX_SETUP_SECTS         63
  #define LINUX_BOOT_LOADER_TYPE                0x71
  #define LINUX_HEAP_END_OFFSET         (0x7F00 - 0x200)
--- 138,144 ----
  #define LINUX_MAGIC_SIGNATURE         0x53726448      /* "HdrS" */
  #define LINUX_DEFAULT_SETUP_SECTS     4
  #define LINUX_FLAG_CAN_USE_HEAP               0x80
! #define LINUX_INITRD_MAX_ADDRESS      0x38000000
  #define LINUX_MAX_SETUP_SECTS         63
  #define LINUX_BOOT_LOADER_TYPE                0x71
  #define LINUX_HEAP_END_OFFSET         (0x7F00 - 0x200)


well, i'm clueless where the original 960MB limit came from (and about
memory layout at all ;-).  anyway, the 0x38000000 barrier was
mentioned in the 2.4.1 boot messages at failure (sorry, i don't have
the message handy to show it).

anyway, at least this report in the archive may help others with the
same trouble.

have fun,
                                                        Erik