On Fri, Sep 5, 2008 at 8:09 AM, Joseph Smith <[EMAIL PROTECTED]> wrote: > > > > On Thu, 4 Sep 2008 23:27:50 -0400, "Corey Osgood" <[EMAIL PROTECTED]> > wrote: >> On Wed, Sep 3, 2008 at 1:26 PM, Mats Erik Andersson >> <[EMAIL PROTECTED]> wrote: >>> >>> Hello again, >>> >>> I have been experimenting with an algorithm to detect >>> and register with the northbridge i440bx the correct >>> amount of sdram present. A C-coded version is appended >>> to this message. Feel free to comment on the method. >>> >>> In the actually working code, I had to split the >>> algorithm into a lower and an upper part, in order >>> not to run out of internal registers under romcc, >>> but the idea remains the same. >>> >>> Since there are also some later stages where I have >>> not understood how the previous author hard coded >>> a single 64MB bank, I presently achieve a running >>> system only when I dynamically detect a distribution >>> identical to what was earlier hard coded. >>> >>> My detection works with any combination of 0MB and >>> 64MB in two rows for DIMM0 and DIMM1. >>> >>> Question: In case an sdram device has rows of mixed >>> sizes, can one depend on the larger density being >>> in row zero, and the smaller content in row one? >> >> Yes. The spd spec assumes the larger row will be row 0, any stick that >> didn't wouldn't follow the standard. At least, that was my >> understanding of it. >> > This can get a little confusing, when you are talking about rows, do you > mean banks? Or actuall sdram slots?
Banks, I assume, all this terminology gets me confuseded. I'm pretty sure Mats was talking about each side of the slot/ram pcb. > As far as it goes with rows/banks, most intel boards only support > asymmetrical sdrams so if the dimm has two sides the second side has to > equal the first side. You mean "only support symmetrical sdrams". IIRC, i810 supports asymmetrical dimms, but I can't remember... -Corey > As far as sdram slots any combination should work as > long as it follows the the northbridge criteria. You can look at the i830 > raminit.c, it has a pretty clever way to detect dimms, and it works every > time no matter what the combination. By the way Uwe was the original author > of the i440bx code. Hope that helps. > > -- > Thanks, > Joseph Smith > Set-Top-Linux > www.settoplinux.org > > -- coreboot mailing list [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
