Help on PMU work

[Super Bisquit]

Right now, I'm stuck at "Need to replace the video cable on my G4 titanium."



On 10/28/12, Justin Hibbits <chmeeedalf at gmail.com> wrote:
> I'm working on getting PMU sleep and speed control working for at least
> the MPC7455-based PowerBooks and running into a snag.  I've got it
> changing speed, but it immediately panics.
>
> The method for PMU speed change is as follows:
> * Tell the PMU to change PLL inputs
> * Save all the needed registers (methinks I missed one or two critical
>   ones, but can't figure out which)
> * Flush and disable the caches
> * Disable NAP and enable SLEEP in HID0
> * Sleep via MSR
> * PMU asserts #HRESET, and jumps to where you want (write address at
>   0x80).
> * Recover and restore all the necessary registers
> * Go on your merry way.
>
> I'm getting stuck on the "Go on your merry way" part.  When it
> recovers, I get a 'panic: null_fetch_syscall_args'.  curthread is the
> same going into and coming out of reset/restore, verified with a printf.
>
> Any help tracking this down is greatly appreciated.  I'll be at MeetBSD
> with my PowerBook, and hope to get it finished either before then, or
> by the time I leave.
>
> - Justin