[LinuxBIOS] 440BX progress.
segher at kernel.crashing.org
Sun Nov 26 23:18:20 CET 2006
> Hint: Try testing the lower memory:
> ram_check(0x10000000, 0x2000000);
> is going for 256-512 Megs.
Ah, there's the (or a) problem. There's a zero missing.
No memory was tested at all.
> The LinuxBIOS image is copied to _RAMBASE which normally defaults to
> 0x4000 (@16k). So you might have 2 dimms a 256M and while the upper one
> works, the lower one doesnt.
> In the end the ram_check() function does not reliably test your memory.
> It will not detect whether your memory works, but it will detect
> it fails ;-)
And not always, either.
> Also note: the order in which your registers are set may play a role.
> For example there might be a register with a DRAM_ENABLE bit which must
> be set last, after all other DRAM related bits are set, or the values
> set later on might be ignored.
Yes. And you often have to wait for certain bits to flip
before you write other bits, etc.
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