[SerialICE] Endless looping through SMBus functions

[Joseph Smith]

On 04/06/2011 04:20 AM, Corey Osgood wrote:
> On Fri, Apr 1, 2011 at 6:43 PM, Joseph Smith<joe at settoplinux.org>  wrote:
>> On 04/01/2011 10:49 AM, Corey Osgood wrote:
>>>
>>> Working on an Atom D500/NM10 system, trying to get some info on memory
>>> init. Everything seems to go alright up to when it starts pulling SPD
>>> data from the SMBus, but for some reason, the stock BIOS performs an
>>> SMBus read at 0x60, checks and sees that the read completed
>>> successfully, clears the success bit, and then, without reading the
>>> data, tries 0x64, and does the same thing. It then moves on to 0x9c,
>>> 0xd3, and 0xd2. I've attached a log file, don't mind my notes. Any
>>> ideas what might be causing this, and how to work around it?
>>>
>> Hmm could be probing to see if devices are present at those addresses? Is
>> there anything there? Thermal sensors?
>
> So, it turns out this board really doesn't like it when I try
> test/dump all 128 SMBus addresses, the SMBus stops working around 69h.
> Not sure if it's because of the number of SMBus operations in a short
> time span, or that SMBus work for very long after init. I did manage
> to figure out that I'm rusty on SMBus, the addresses are all shifted
> to the left one, so the address it's really trying to probe are 30h,
> 32h, 4Eh, and 69h, all of which have devices of some kind on them,
> although I'm not sure if they're all sensors (kinda doubt it, but it's
> possible) or for other functions like TV-out or clock controls. Also,
> these are both read and write functions, and mostly write. It seems
> like the SMBus only stays working for a short period of time after it
> gets initialized, and I think the problem is that SerialICE makes the
> SMBus operations take so much longer that they start failing before
> the system has everything set up. So, I'm thinking there are a couple
> options, one being to modify the lua script to not log access to the
> SMBus addresses, but I don't think that will help much, because it
> just eliminates printing the text to the screen (afaik). The other
> being to try a BIOS from a really cheap NM10 board, that's not likely
> to have the configurable clock chips and TV out, since all I'm really
> interested in is RAM init, for the time being. Any opinions?
>
Well I think you need option one. You need to be able to read memory 
SPD's on the smbus.


-- 
Thanks,
Joseph Smith
Set-Top-Linux
www.settoplinux.org