ron minnich wrote:
Your memory is still wrong. 0x67 ... oh boy. I am working from memory here. At some point the chipset added two more DBR registers -- I wonder if this is it.
Sorry but it's been 6 years ... I will try to find my books and see what that might be.
thanks
ron
I think maybe reg 0x67 is misleading. I have a feeling that the problem may not be with the configuration of the northbridge, but more to do with timing. Currently I am setting reg 0x67 at the end of sdram_set_registers(). If it is there the boot process gets further. If I take it out I get errors with something else, can't remember what exactly. I need to test if the extra delay is meaningful all be it very short, or if writing to the register is actually doing something. I originally tried setting reg 0x67 further down inside sdram_enable() but it did not have any effect there. Of course that could just mean it needs to be set earlier.
As far as I can see reg 0x67 has never been set in any of the version of Linuxbios I have looked at, and as it has worked in the past I think it is probably not important. Just because the original bios is setting it, doesn't mean that it is right either.
Who wrote the original vt8601 code ? The vt8601a datasheet makes mention of "VT8601A BIOS porting guide" but I can't find it anywhere. Perhaps I will have to email VIA and see if they would be good enough to send me a copy.