Question: Can I change DQS settings from a user program

[Fengwei Zhang]

Hi all,

I have a K8 board. I tried to change the DQS settings from a user 
program, but I failed.
I printed out the DQS settings before my pci_write_long() function. I 
also printed out the DQS settings after the pci writing. The results are 
same.

My question is: can I change DQS settings from a user program? or I need 
to enable some registers before changing?

Thanks,
Fengwei

Question: Can I change DQS settings from a user program

[Stefan Reinauer]

On 2/18/11 2:48 PM, Fengwei Zhang wrote:
> Hi all,
>
> I have a K8 board. I tried to change the DQS settings from a user 
> program, but I failed.
> I printed out the DQS settings before my pci_write_long() function. I 
> also printed out the DQS settings after the pci writing. The results 
> are same.
>
> My question is: can I change DQS settings from a user program? or I 
> need to enable some registers before changing?

I believe you have to do this during RAM init as it will potentially 
compromise the contents of your RAM. Thus it can not be done after an OS 
has started.

What's the rationale here?

Stefan