prompt_ramdisk=1 and load_ramdisk=1 doesn't work with 2.6.11 on floppy

prompt_ramdisk=1 and load_ramdisk=1 doesn't work with 2.6.11 on floppy

[Tetsuji "Maverick" Rai]

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I am making a small boot-floppy linux distro with kernel 2.6.11.   The
kernel is so big that I need to load ramdisk from the second floppy
and I don't use initrd.   My problem is the kernel wouldn't prompt to
load ramdisk image.  I tried syslinux, grub and lilo as boot loader
and for syslinux, I put syslinux.cfg as follows:
- --------------
DEFAULT bzImage noinitrd ramdisk_size=10240 ramdisk_start=0
prompt_ramdisk=1 load_ramdisk=1 root=/dev/ram0 disksize=1.44
prompt 1
timeout 50
- ---------------

kernel boots as usual, however it stops without loading ramdisk floppy
saying:

- -----------
Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(1,0)
- -----------
This error message makes sense because it hasn't loaded ramdisk image
(block(1,0) means /dev/ram0, IMHO).  But in my kernel configuration,
ramdisk is enabled and the default size is 8192kb.  The boot message
says the size of ramdisk is 10240kb, so I guess the kernel recognizes
kernel options.  Then why doesn't prompt for the ramdisk floppy?

I've read syslinux is not compatible with kernel 2.6.something in this
mailing-list archive, tried with grub and lilo with the same kernel
options, but in vain..  so I guess the loader doesn't matter.

Thanks in advance!

- --
Tetsuji Rai (in Tokyo) aka AF-One (Athlete's Foot-One) Maverick6664
Maverick's Linux http://maverick.trickip.net/
Aviation jokes http://www.geocities.com/tetsuji_rai
Profile http://maverick.ns1.name/
maverick6664@abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijk.com
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Re: prompt_ramdisk=1 and load_ramdisk=1 doesn't work with 2.6.11 on floppy

[Andrew Morton]

"Tetsuji \"Maverick\" Rai" <badtrans666@yahoo.co.jp> wrote:
>
> I am making a small boot-floppy linux distro with kernel 2.6.11.   The
>  kernel is so big that I need to load ramdisk from the second floppy
>  and I don't use initrd.   My problem is the kernel wouldn't prompt to
>  load ramdisk image.  I tried syslinux, grub and lilo as boot loader
>  and for syslinux,

The basic mechanism seems to work OK here.  I couldn't be bothered setting
up a floppy so I patched things:

--- 25/init/do_mounts_rd.c~a	2005-03-22 19:16:22.000000000 -0800
+++ 25-akpm/init/do_mounts_rd.c	2005-03-22 19:16:26.000000000 -0800
@@ -12,7 +12,7 @@
 
 #define BUILD_CRAMDISK
 
-int __initdata rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
+int rd_prompt = 1;/* 1 = prompt for RAM disk, 0 = don't prompt */
 
 static int __init prompt_ramdisk(char *str)
 {
diff -puN init/do_mounts.c~a init/do_mounts.c
--- 25/init/do_mounts.c~a	2005-03-22 19:32:53.000000000 -0800
+++ 25-akpm/init/do_mounts.c	2005-03-22 19:41:38.000000000 -0800
@@ -371,8 +371,7 @@ void __init mount_root(void)
 		ROOT_DEV = Root_FD0;
 	}
 #endif
-#ifdef CONFIG_BLK_DEV_FD
-	if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
+	if (1) {
 		/* rd_doload is 2 for a dual initrd/ramload setup */
 		if (rd_doload==2) {
 			if (rd_load_disk(1)) {
@@ -382,7 +381,6 @@ void __init mount_root(void)
 		} else
 			change_floppy("root floppy");
 	}
-#endif
 	create_dev("/dev/root", ROOT_DEV, root_device_name);
 	mount_block_root("/dev/root", root_mountflags);
 }
_


The machine does pause at the prompt.

So I'd suggest that you need to start sticking printk()s into mount_root(),
rd_load_disk() and change_floppy(), see if you can work out what's
happening.