[U-Boot] Help!Some memory doesn't work on PPC405Ex based board!

[Stefan Roese]

Sun,

On Thursday 23 April 2009, Grant Erickson wrote:
> On 4/22/09 10:00 PM, SunNeo wrote:
> > I got a new board with 1GB DDRII memory and only 1 Rank, but the problem
> > still exist.
> >
> > The following is a summary of my job:
> >
> > 4. Have performed memory test with "mtest" command at U-Boot, no error
> >    happened.
>
> Sun:
>
> It's been awhile since I looked at the code for mtest; however, it may not
> be entirely comprehensive or exhaustive depending on how you configured
> your u-boot build and the arguments you invoked it with. Do verify that it
> is operating over the largest range of RAM possible and that it is doing an
> array of tests (walking 1s, alternating bit patterns, etc.).

Take a look at the mem test included in the POST framework 
(post/drivers/memory.c). This should be more extensive.

<snip>

> > 9. Add the parameter "mem=516M" to bootargs, Linux can boot up normally.
> > But if add "mem=517M" to bootargs, Linux hangs.
>
> That should be instructive. Start tweaking mtest or writing your own memory
> tests to tease out a pattern from that. Failing that, what other values
> work here? What values fail?

And I'm wondering why you are using such an old Linux kernel version. I 
suggest to at least test a recent arch/powerpc version. Perhaps this gives 
other results.

Best regards,
Stefan

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