[LinuxBIOS] Read SPD issue

Joseph Smith joe at smittys.pointclark.net
Sun Aug 12 08:03:35 CEST 2007

Quoting Corey Osgood <corey.osgood at gmail.com>:

>> So, I tried the
>>     dump_spd_registers(&memctrl[0]);
>>     dump_smbus_registers();
>> from debug.c and here is the results:
>> -----------------
>> LinuxBIOS- Sat Aug 11 21:37:10 EDT 2007 starting...
>> dimm: 00.0: 50
>> 00: bad device
>> dimm: 01.0: 51
>> 00: bad device
>> smbus: 69
>> ----------------
>> HELP???
>> Thanks - Joe
> In the attached debug.c is probe_spd_rom(). If your device has spd, it
> should be able to find it. You can use the whole file and #include it
> into the southbridge or mainboard or even northbridge code, or just copy
> and paste it into somewhere else. Call it whereever you called
> dump_spd_registers from. Note that it's not magic (yet), it won't
> actually use found spd locations, you'll have to do that manually. Also,
> what make/model is your dimm and board (I know you've told me, but my
> memory is terrible)? The datasheets may have more info, if they're
> available.
> -Corey
So I tried the probe_spd_rom() and it comes back with "bad device".  
Which I expected because this line in the function

status = smbus_read_byte(i, 0);

is my whole problem:( The smbus_read_byte function is what is not  
working in raminit.c so why would it work when called from auto.c?? No  
matter what byte I try to read it just comes back with a 0xFF ??

Here is a recap of the hardware:
RCA RM4100 Embedded Set-top-box
Low Voltage Intel® Celeron® processor (Micro-FC-BGA) 733MHz
128MB PC133 SDRAM on board (Embedded) (In Socket2)
Intel i82830 (i830M4) Northbridge (Developing)
Intel i82801DB Southbridge (Using i82801xx)
SMSC lpc47m192 SuperIO (Using smscsuperio)

This is making me crazy, I'm so confused?

Thanks - Joe

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