[coreboot] what should CONFIG_HT_CHAIN_UNITID_BASE be in "CPU/1HT device" mode?

Bao, Zheng Zheng.Bao at amd.com
Wed Nov 4 07:11:43 CET 2009

Hi, Myles,
About the HT code, I have a question.

I am debugging my board, which is Fam10+RS780+SB700. The CPU and RS780 are the two HT node. It seems like the RS690/SB600 board. In early_ht.c, the comment in enumertate_ht_chain() says,

/* CONFIG_HT_CHAIN_UNITID_BASE could be 0 (only one ht device in the ht chain), 
if so, don't need to go through the chain  */

I am wondering if the CONFIG_HT_CHAIN_UNITID_BASE is 0 in my case. If not, why in the supported RS690/SB600 board, the CONFIG_HT_CHAIN_UNITID_BASE is 0.



From: Marc Jones [mailto:Marc.Jones at applieddesigncorp.com] 
Sent: Wednesday, November 04, 2009 7:31 AM
To: Bao, Zheng
Cc: Writer, Tim; Xie, Michael; Ni, John; Wang, Qingpei
Subject: RE: coreboot 780/710 review

I am not sure that you made a good change. I don't completely understand the defines either. These settings are for the pre-HT init and I don't know how much should be setup.  Some of the problems come in when the pre-HT init and the fam10 init don't agree on the UNITID setting. Do you know what the UNITIDs end up as with the legacy bios?  
I was not clear how this was breaking for you and what your change did. I think that setting CHAIN_UNITID_BASE=0 is wrong since you have two HT devices, CPU, 780/710? 780 is considered the SB since it is Alink to the 710 right? SB_HT_CHAIN_ON_BUS0=1 should put the SB on bus 0. I am not sure about UNITID_OFFSET being set or not. I think that some early HT SB (CHAIN_END_UNITID) had to be hardcoded to 0x6, but ATI doesn't have that problem and you can leave the default setting of 0x20. You can try asking on the coreboot list as well. Myles has been working on the HT code a lot.
I think that these settings should work:
#HT Unit ID offset, default is 1, the typical one, 0 mean only one HT device

#real SB Unit ID, default is 0x20, mean dont touch it at last

#make the SB HT chain on bus 0, default is not (0)

#only offset for SB chain?, default is yes(1)
Also, Note that the coreboot svn was reorganized yesterday. Try to make a patch based on the new tree.

More information about the coreboot mailing list