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RE: Help in enabling HIGHMEM support / 64 bit support

To: "Ralf Baechle" <>
Subject: RE: Help in enabling HIGHMEM support / 64 bit support
From: "Anoop P.A." <>
Date: Mon, 18 Jan 2010 07:57:06 -0800
Cc: <>
In-reply-to: <>
References: <> <> <>
Thread-index: Acp848y7wxTUpEk6QWCQk4x5wrla0wbbQfEg
Thread-topic: Help in enabling HIGHMEM support / 64 bit support

I am working on enabling Highmem support and 64 Bit support

1. 64 Bit support

As Ralf suggested I have tried enabling 64 bit support. I have reached
up to a point where I can boot the kernel with 512MB memory (logs
attached). How ever if I increase mem above > 512 I am not even getting
single print from kernel. 
I am blocked at this point. I will appreciate if any body can point me
to a most likely issue that I am hitting. BTW I am running kernel 2.6.18

2. Highmem 

I have tried enabling highmem. And I could boot till mounting root file
system. I have tried mounting RFS from a usb disk as well as NFS mount.
Both the cases fails (attaching logs). 

Let me know if you guys need any further info for giving me some


-----Original Message-----
From: Ralf Baechle [] 
Sent: Monday, December 14, 2009 11:05 PM
To: Anoop P.A.
Subject: Re: Help in enabling HIGHMEM support

On Mon, Dec 14, 2009 at 05:34:13AM -0800, Anoop P.A. wrote:

> We have a requirement to use a bigger RAM (1 GB / 2GB) with a RM9000
> based SOC. I thought of going with HIGHMEM path rather than enabling
> 64bit support thinking it will be easier.

This sounds like sawing off 32 legs just to be able to make use of a
free [1] wheelchair.

> I have tried enabling HIGMEM in kernel. Board boots fine with a 512 MB
> RAM plugged in. But if I connect a 1 GB RAM kernel will not boot. I am
> not even getting single print from kernel. I am using linux-2.6.18
> kernel.
> It will be great if get any pointers suggestions in debugging this?

With this amount of RAM, use a 64-bit kernel if you can.  You'll be
happy not to know about all the headaches you will never encounter.


[1] Conditions apply.

Attachment: highmem-squashfs.doc
Description: highmem-squashfs.doc

Attachment: highmem-nfs.doc
Description: highmem-nfs.doc

Attachment: 64bit-1024MB.doc
Description: 64bit-1024MB.doc

Attachment: 64bit-512MB.doc
Description: 64bit-512MB.doc

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