Re: some questions on new dual 1Gig G4's support?
From: Kevin B. Hendricks <hidden>
Date: 2002-02-04 18:27:26
Hi Ben,
No. It's 2 things. First the NAP must be disabled depending on the errata (7450 + L3), but also, neither the 7450 nor the 7455 support DOZE, they can only NAP or do nothing. Worst, on the 7455, it's bad to set HID0:DOZE as it actually has a different meaning.
Yes, that is the HIGH_BAT_EN (bit 8) of HID0 which I think we should leave as zero to keep the 7455 compatible with the 7450. I know nothing about BAT registers or how to take advantage of block sizes up to 4 Gig, and I also do not know if/how we should handle the 4 extra special purpose registers (supevisor mode only). Some sample exception handling code uses these extra SPRG registers to hand;le BAT table exceptions to speed things up. Someone who actually knows a whole lot more about the best way to use BATs will have to take a look at all of these extra pieces.
So let's split the can doze & can nap into 2 different features.
I will do that in cputable.h as you said.. But what about the SLEEP mode my last e-mail mentioned. It is a different mode from NAP (does no bus snooping) but saves more power. Thanks, Kevin ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/