VFS: Cannot open root device "31:03" or unknown-block(31,3)

VFS: Cannot open root device "31:03" or unknown-block(31,3)

[HappyPhot]

Hi,
  I've suffered for many days and "google" almost every where.
I would like to boot from the flash with jffs2 (i.e. using jffs2 as my
root /) . But it alyaws shows:
VFS: Cannot open root device..... (whole message is as below)

  Anybody knows what may cause this ? Please help and
thank you.

/HappyPhot

==============(booting message)==================
.......
physmap flash device: 1000000 at 70000000
phys_mapped_flash: Found 2 x8 devices at 0x0 in 16-bit bank
 Intel/Sharp Extended Query Table at 0x0031
Using buffer write method
cfi_cmdset_0001: Erase suspend on write enabled
5 cmdlinepart partitions found on MTD device phys_mapped_flash
Creating 5 MTD partitions on "phys_mapped_flash":
0x00000000-0x00200000 : "k4"
mtd: Giving out device 0 to k4
0x00200000-0x00400000 : "k6"
mtd: Giving out device 1 to k6
0x00400000-0x00800000 : "rd"
mtd: Giving out device 2 to rd
0x00800000-0x00c00000 : "jffs2"
mtd: Giving out device 3 to jffs2
0x00c00000-0x02000000 : "others"
mtd: Giving out device 4 to others
VFS: Cannot open root device "31:03" or unknown-block(31,3)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on 
unknown-block(31,3)
 <0>Rebooting in 180 seconds..
========================================== 

Re: VFS: Cannot open root device "31:03" or unknown-block(31,3)

[David Jander]

On Monday 02 January 2006 15:48, HappyPhot wrote:
> Hi,
>   I've suffered for many days and "google" almost every where.
> I would like to boot from the flash with jffs2 (i.e. using jffs2 as my
> root /) . But it alyaws shows:
> VFS: Cannot open root device..... (whole message is as below)
>
>   Anybody knows what may cause this ? Please help and
> thank you.
>[...]

You omitted the interesting part of the log output, the bootarguments at the 
very beginning. What is the value of root= ?
Maybe you made the typical mistake of specifying /dev/mtd3 instead 
of /dev/mtdblock3, or you didn't compile in support for mtd access as a block 
device?

Greetings,

-- 
David Jander

Re: VFS: Cannot open root device "31:03" or unknown-block(31,3)

[HappyPhot]

> On Monday 02 January 2006 15:48, HappyPhot wrote:
>> Hi,
>>   I've suffered for many days and "google" almost every where.
>> I would like to boot from the flash with jffs2 (i.e. using jffs2 as my
>> root /) . But it alyaws shows:
>> VFS: Cannot open root device..... (whole message is as below)
>>
>>   Anybody knows what may cause this ? Please help and
>> thank you.
>>[...]
>
> You omitted the interesting part of the log output, the bootarguments at 
> the
> very beginning. What is the value of root= ?
> Maybe you made the typical mistake of specifying /dev/mtd3 instead
> of /dev/mtdblock3, or you didn't compile in support for mtd access as a 
> block
> device?
>

Hi, David and all,
  I've tried root=/dev/mtdblock3, root=/dev/mtd3, root=31:03 etc.  And 
"Caching
block device access to MTD devices" was also selected when 'make 
menuconfig'.
The results were the same.
  I use "phys_mapped_flash" and "mtdparts=phys_mapped_flash:2M(k4),2M(k6),
4M(rd),4M(jffs2),-(User_Data)". What is the "root=" I should use ?

  Also, I am wondering how the kernel knows "/dev/mtdblock3" is in my flash 
?
I think I never do any setting about this....

thank you ,
/HappyPhot

Re: VFS: Cannot open root device "31:03" or unknown-block(31,3)

[David Jander]

On Thursday 05 January 2006 04:29, you wrote:
> Hi, David,
>   I get the complete bootlog and .config here. Please see the
> attached files. I copy the bootlog into .config.
>   And my NFS can mount root file system ok, but can not
> execute any program. Once the program load into system and
> run, the system crash.
>   I am new in this field and thank you for your help.
> Regards,
> /HappyPhot

in your .config:

> CONFIG_JFFS2_FS=m

This is wrong. You have to choose "y", not "m" (for module).
This way jffs2 is compiled as a module. That means, that jffs2 filesystem will 
not be available until the module is loaded with "insmod jffs2" of something 
similar. That in turn means that your system has to start up first in order 
to be able to do this, but since you can't start because your root filesystem 
is on jffs2, you have created yourself a "chicken and egg" problem.
If you choose "y" then jffs2 support will be compiled into the kernel, and 
thus be available before booting.

In your bootlog:

> Linux version 2.6.14.2 (happy@sddlinux1) (gcc version 3.3.3 (DENX ELDK 3.1.1 
> 3.3.3-10)) #29 Sun Jan 1 22:34:28 CST 2006
> Motorola SPS Sandpoint Test Platform

I see you are using DENX ELDK 3.1.1 and a kernel which AFAIK is not supported 
by this version of ELDK. Are you sure this is supposed to work? It probably 
will, but I don't know what the "Sandpoint" is (it looks like a PowerPC 
processor of the MPC7xx series to me), so I couldn't tell.

Greetings,

-- 
David Jander

Re: VFS: Cannot open root device "31:03" or unknown-block(31,3)

[HappyPhot]

> in your .config:
>
>> CONFIG_JFFS2_FS=m
>
> This is wrong. You have to choose "y", not "m" (for module).
> This way jffs2 is compiled as a module. That means, that jffs2 filesystem 
> will
> not be available until the module is loaded with "insmod jffs2" of 
> something
> similar. That in turn means that your system has to start up first in 
> order
> to be able to do this, but since you can't start because your root 
> filesystem
> is on jffs2, you have created yourself a "chicken and egg" problem.
> If you choose "y" then jffs2 support will be compiled into the kernel, and
> thus be available before booting.

Hi, David,
  Yes, you are right. After changing it to 'y', the " VFS: Cannot open 
root..."
message was gone. I'm so happy and thank you very much.

  Now it is another problem again. (something like: Oops: kernel access of 
bad
area. sig:11...).  I am going to check what happened.

>
> In your bootlog:
>
>> Linux version 2.6.14.2 (happy@sddlinux1) (gcc version 3.3.3 (DENX ELDK 
>> 3.1.1
>> 3.3.3-10)) #29 Sun Jan 1 22:34:28 CST 2006
>> Motorola SPS Sandpoint Test Platform
>
> I see you are using DENX ELDK 3.1.1 and a kernel which AFAIK is not 
> supported
> by this version of ELDK. Are you sure this is supposed to work? It 
> probably
> will, but I don't know what the "Sandpoint" is (it looks like a PowerPC
> processor of the MPC7xx series to me), so I couldn't tell.

  Do you know where to get the infomation about which kernel version it 
supports?

thank you,
/HappyPhot

Re: VFS: Cannot open root device "31:03" or unknown-block(31,3)

[David Jander]

On Friday 06 January 2006 15:09, HappyPhot wrote:
> > I see you are using DENX ELDK 3.1.1 and a kernel which AFAIK is not
> > supported
> > by this version of ELDK. Are you sure this is supposed to work? It
> > probably
> > will, but I don't know what the "Sandpoint" is (it looks like a PowerPC
> > processor of the MPC7xx series to me), so I couldn't tell.
>
>   Do you know where to get the infomation about which kernel version it
> supports?

The one that comes with that version of ELDK? Just a guess ;-)

Greetings,

-- 
David Jander

Re: VFS: Cannot open root device "31:03" or unknown-block(31,3)

[Wolfgang Denk]

In message <200601061519.14550.david.jander@protonic.nl> you wrote:
>
> > > I see you are using DENX ELDK 3.1.1 and a kernel which AFAIK is not
> > > supported

This is a serious misunderstanding. There is no  such  thing  like  a
specific kernel version which is supported by the ELDK.

You don't talk about any specific version of a  C  programm  that  is
supported by the GNU compiler either.


The ELDK is primarily a *toolkit* which works with  arbitrary  C  and
C++  programs  and  with  any version of the kernel tree (at least in
theory; very recent version s of the Linux kernel [ > 2.6.14]  cannot
be compiled with ELDK 3.1.x any more, but this is a different issue).

> >   Do you know where to get the infomation about which kernel version it
> > supports?

The ELDK supports *any* kernel version.

> The one that comes with that version of ELDK? Just a guess ;-)

Wrong guess.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
"I've seen it. It's rubbish."          - Marvin the Paranoid Android

Re: VFS: Cannot open root device "31:03" or unknown-block(31,3)

[David Jander]

On Friday 06 January 2006 16:08, Wolfgang Denk wrote:
> This is a serious misunderstanding. There is no  such  thing  like  a
> specific kernel version which is supported by the ELDK.

True, but not entirely.
ELDK-3.1.1 has a glibc compiled with support of a certain version of the 
kernel (I guess it's 2.4.xx), so newer kernels might run (because they are 
obviously backwards compatible), but some features of 2.6 cannot be used 
(e.g. support for the latest syscalls, different HZ, etc...)

A second issue is the boot procedure. If you are a beginner with linux, you'd 
probably start booting from NFS root as it gets installed in the ELDK/ppc_xxx 
directory. That probably won't work very well with latest 2.6 kernels (device 
files missing, sysfs not mounted, shmfs has different name, etc...)

A third issue is the compiler issue. Some newer kernels might not compile 
correctly anymore with older compilers.

These three things are what I meant with "supported" or "not supported".

> The ELDK is primarily a *toolkit* which works with  arbitrary  C  and
> C++  programs  and  with  any version of the kernel tree (at least in
> theory; very recent version s of the Linux kernel [ > 2.6.14]  cannot
> be compiled with ELDK 3.1.x any more, but this is a different issue).

See what I mean? HappyPhot did just that: compile 2.6.14.2 with ELDK 3.1.1!!!

> > >   Do you know where to get the infomation about which kernel version it
> > > supports?
>
> The ELDK supports *any* kernel version.

Ok, let's talk about "recommended" kernel then. I would never recommend 
someone unexperienced to start with a combination of ELDK-3.1.1 and kernel 
2.6.xx.

> > The one that comes with that version of ELDK? Just a guess ;-)
>
> Wrong guess.

But it'd still be the one with most chances of success unless there are known 
problems with that kernel on a Sandpoint board.

Greetings,

-- 
David Jander
Protonic Holland.

Re: VFS: Cannot open root device "31:03" or unknown-block(31,3)

[Wolfgang Denk]

In message <200601090945.22564.david.jander@protonic.nl> you wrote:
>
> ELDK-3.1.1 has a glibc compiled with support of a certain version of the 
> kernel (I guess it's 2.4.xx), so newer kernels might run (because they are 

They do run.

> obviously backwards compatible), but some features of 2.6 cannot be used 
> (e.g. support for the latest syscalls, different HZ, etc...)

You can also change HZ if you like.

> A second issue is the boot procedure. If you are a beginner with linux, you'd 
> probably start booting from NFS root as it gets installed in the ELDK/ppc_xxx 
> directory. That probably won't work very well with latest 2.6 kernels (device 
> files missing, sysfs not mounted, shmfs has different name, etc...)

You can (mis-) configre  a  2.4  kernel  too.  Using  a  sane  kernel
configuration  ther  ewill  be  no  problems. We have been using ELDK
3.1.1 for a long time ourself developing 2.6 kernel code.

> > C++  programs  and  with  any version of the kernel tree (at least in
> > theory; very recent version s of the Linux kernel [ > 2.6.14]  cannot
> > be compiled with ELDK 3.1.x any more, but this is a different issue).
> 
> See what I mean? HappyPhot did just that: compile 2.6.14.2 with ELDK 3.1.1!!!

I wrote "> 2.6.14"; 2.6.14.2 is just a branch off 2.6.14 and is  fine
AFAICT.

> > The ELDK supports *any* kernel version.
> 
> Ok, let's talk about "recommended" kernel then. I would never recommend 

There is no recommended kernel version. On contrary,  we  take  great
efforts  to keep the ELDK independent of speicfic kernelk versions as
far as possible.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
Quantum particles: The dreams that stuff is made of.