RE: [Linux-fbdev-users] atyfb: brokenness on PowerMac 5500 and Beige G3

[Gil B. <co...@ba...>]

Hello,

I have now decoded and mapped the register differences as they appeared in
http://patchwork.ozlabs.org/linuxppc/patch?id=1268. However, I have went
through the code path and cannot explain most of the reasons for the
changes, nor can I estimate their effect. That's where the list might come
handy :)

So, after applying the patch:

BUS_CNTL changes from 7b23a040 to 7b23a050. this is due to the code section
that enables auxillary aperture to enable access to 8mb memory cards.

CRTC_GEN_CNTL changes from 03000200 to 0b000200. I have noticed the code in
mach64_ct.c has removed a particular bit masking when assigning GEN_CNTL,
but I have no idea why.

DSP_CONFIG also changes. It becomes 004805FA instead of 004808e2. no idea
why - the code that generates it looks the same to me.

DSP_ON_OFF also changes. It becomes 00B4043B instead of 009C0666. ditto for
the reasoning.

PLL is also different in its first 24 bytes:
ADD52414 instead of ADD52144
A80382D1 instead of E80382D1
8E829601 instead of 8E9E9814
I don't know how to decode this yet.

Can anyone have a look at mach64_ct.c and maybe notice what I haven't
noticed regarding the DSP programming?

Thanks,

Gil Bahat,
System Administrator.