Quoting Jordan Crouse jordan.crouse@amd.com:
On 01/10/07 21:06 -0400, joe@smittys.pointclark.net wrote:
Quoting ron minnich rminnich@gmail.com:
On 10/1/07, joe@smittys.pointclark.net joe@smittys.pointclark.net wrote:
c. It is located in the second slot not first.
hmm. could this second slot somehow have a different base physical address? unlikely but this is getting confusing.
ron
I don't think so. Your telling me. I am so confused right now I'm starting to get a migrane. I can't for the life of me figure out why this is choking. Everything seems to be ok right up to the jmp_to_elf_entry() function. Then it chokes at the assembly part. Does that make sense??
Absolutely - if your memory is hosed, this will be the first place that you'll run afowl of it, especially when it comes to the top of memory. Because whats happening at this point is that LinuxBIOS is copying some part of itself to the top of memory to make room for the payload. If your memory map is wierd, then this will easily be the first place where it will be exposed.
Jordan
LinuxBIOS does get copied to TOM? From looking at the code it just looks like it just doubles LB's size and then copies it there (bounce buffer). If it is getting copied to TOM that explains everything. The Internal graphics is supposed to pre-allocate memory from TOM down. From the i82830 datasheet:
-------------------------------------------- These Register Bits control the theft of memory from Main Memory space for use as Graphics memory. The memory for TSEG is pre-allocated first and then the Graphics memory is pre-allocated. An example of this theft mechanism is:
TOM equal 64 MB, TSEG selected as 512 KB in size, Graphics memory selected as 1 MB in size General System RAM available in system = 62.5 MB General System RAM Range 00000000h to 03E7FFFFh TSEG Address Range 03F80000h to 03FFFFFFh TSEG pre-allocated from 03F80000h to 03FFFFFFh Graphics memory pre-allocated from 03E80000h to 03F7FFFFh -----------------------------------------------
I don't have TSEG enabled though. I wonder if I did though, it would give LB extra space for it's bounce buffer?? Does this make any sense?
Thanks - Joe