ppcboot, linux , hang at the last step

ppcboot, linux , hang at the last step

[caixupeng]

Dear all,

When I boot a linux image use "bootm ffa00000 ffb00000"
the linux hang at the last step:

VFS: Cannot open root device "" or 16:01
Please append a correct "root=" boot option
Kernel panic: VFS: Unable to mount root fs on 16:01

I have set the "bootargs=root=/dev/ram"

what's wrong ?

Is my linux kernel's erro or ppcboot's problem?
Does ppcboot send the bootargs to linux kernel correctly?

Where can set the boot params in the linux source code ?
I want to set the params in code to force it correctly.

I use linux-2.4-develop-rc1 which download from bitkeeper.

my board is Ebony.

thanks!

                    edmoon

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Re: ppcboot, linux , hang at the last step

[Marius Groeger]

On Mon, 25 Nov 2002, caixupeng wrote:

> VFS: Cannot open root device "" or 16:01
> Please append a correct "root=" boot option
> Kernel panic: VFS: Unable to mount root fs on 16:01
>
> I have set the "bootargs=root=/dev/ram"

Try "setenv bootargs root=/dev/ram0 rw" in ppcboot.

Regards,
Marius

-----------------------------------------------------------------------------
Marius Groeger           SYSGO Real-Time Solutions AG       mgroeger@sysgo.de
Software Engineering     Embedded and Real-Time Software    www.sysgo.de
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Re: ppcboot, linux , hang at the last step

[Wolfgang Denk]

In message <000d01c29471$ca5b94d0$92690b0a@DBKQW41X> you wrote:
>
> When I boot a linux image use "bootm ffa00000 ffb00000"
> the linux hang at the last step:
>
> VFS: Cannot open root device "" or 16:01
> Please append a correct "root=" boot option
> Kernel panic: VFS: Unable to mount root fs on 16:01
>
> I have set the "bootargs=root=/dev/ram"

Is this your input, or the putput of the printenv command in PPCBoot?
Remember that you must not use a '=' with setenv!

> Is my linux kernel's erro or ppcboot's problem?

Which arguments are really passed to Linux?  The  kernel  prints  the
boor arguments it receives on the console.

> Does ppcboot send the bootargs to linux kernel correctly?

It does. Probably you did not specifyu correct boot arguments.


Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
You've no idea of what a poor opinion  I  have  of  myself,  and  how
little I deserve it.                                  - W. S. Gilbert

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Re: ppcboot, linux , hang at the last step

[Omanakuttan]

caixupeng wrote:
 > but, can you tell me the detail?
 >
 > Does it mean  the kernel has build in ramdisk ?
No. The kernel does not have a built in ramdisk. but it uses the ramdisk
image passed for modules and the like. correct me if I am wrong.
 > or you have to give a ramdisk separately to the kernel boot args?
initrd='ramdisk image' is the option I gave.
I am not very much conversant with linux booting procedure, but I
believe that the initrd image takes all the dependent modules and link
them properly when the kernel is booting up. So even if you choose fs
support in modular format, it will be loaded by the initrd image.

 >>when I passed the initrd option into the kernel.
 >
 > the option is " root=/dev/ram ",  right?
Frankly, I am not sure. someone else might be able to help you.

Thanks and regards,
Om.

caixupeng wrote:
 > very very thanks.
 >
 > but, can you tell me the detail?
 >
 > I didn't choose advanced partion features.
 >
 > and I chose ext2 fs support, and initrd support too.
 >
 > there is a size of ramdisk set in linux config,
 >
 > Does it mean  the kernel has build in ramdisk ?
 > or you have to give a ramdisk separately to the kernel boot args?
 >
 >
 >>when I passed the initrd option into the kernel.
 >
 > the option is " root=/dev/ram ",  right?
 >
 > thank you very much!
 >
 >             edmoon
 >
 > ----- Original Message -----
 > From: "Omanakuttan" <omanakuttan@tataelxsi.co.in>
 > To: "caixupeng" <edmoon@huawei.com>
 > Sent: Tuesday, November 26, 2002 1:03 PM
 > Subject: Re: ppcboot, linux , hang at the last step
 >
 >
 >
 >>caixupeng wrote:
 >>
 >>>When I boot a linux image use "bootm ffa00000 ffb00000"
 >>>
 >>>VFS: Cannot open root device "" or 16:01
 >>>Please append a correct "root=" boot option
 >>>Kernel panic: VFS: Unable to mount root fs on 16:01
 >>>
 >>>I have set the "bootargs=root=/dev/ram"
 >>
 >>I faced the same problem, not on ebony.
 >>My configuration was wrong.
 >>1. i did not compile in the advanced partition features and consequently
 >>kernel could not recognize my hda.
 >>2. The problem still persisted. I found out the file system support was
 >>absent. I compiled ext2 fs support into the kernel and tried.
 >>3. I had to create an initrd image using mkinitrd, and all worked fine
 >>when I passed the initrd option into the kernel.
 >>
 >>HTH.
 >>Om.
 >>
 >
 >


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Re: ppcboot, linux , hang at the last step

[Wolfgang Denk]

In message <3DE33302.4070907@tataelxsi.co.in> you wrote:
>
> No. The kernel does not have a built in ramdisk. but it uses the ramdisk
> image passed for modules and the like. correct me if I am wrong.

Please do not confuse the usage of  a  ramdisk  image  with  standard
distributions  like RedHat etc. With Embedded Systems a ramdisk image
usually severs a bit a different purpose.

>  > or you have to give a ramdisk separately to the kernel boot args?
> initrd='ramdisk image' is the option I gave.

This may be correct with some boot loader like LILO, bot it i s not a
valid kernel boot argument.

>  > the option is " root=/dev/ram ",  right?
> Frankly, I am not sure. someone else might be able to help you.

Yes, "root=/dev/ram" (or usually "root=/dev/ram rw") is  the  correct
kernel boot argument for booting with an initial ramdisk image.

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
"The computer programmer is a creator of universes for which he alone
is responsible. Universes of virtually unlimited  complexity  can  be
created  in  the  form  of  computer  programs." - Joseph Weizenbaum,
_Computer Power and Human Reason_

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