[coreboot] Cold reset in Tyan s2912

Roman Kononov kononov at dls.net
Tue Feb 5 16:48:01 CET 2008

On 2008-02-05 00:48 yhlu said the following:
> On Feb 4, 2008 9:29 PM, Roman Kononov <kononov at dls.net> wrote:
>> I have difficulty cold-resetting Tyan s2912, which has mcp55.
>> The sequence
>>      outb(0x2,0xcf9);
>>      outb(0x6,0xcf9);
>> is a warm reset. It does not reset the HyperTransport link frequency and width.
> how do you know?
> do you have other co-processor or htx installed?

I have a co-processor.

The sequence I hope to have:

1) Power up. Power-on reset. The co-processor takes long time to become 
alive (~500s). By this time the CPU thinks that the HT link is dead.
2) CPU issues another reset.
3) The CPU re-initializes the HT link and the connection is happy.

With the above sequence, the step 3) is a warm reset, and the CPU does 
not attempt to re-initialize the link.

> YH


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