Re: Heads up: new SD controller driver for Raspberry Pi in -current

[Jared McNeill <jmcneill%invisible.ca@localhost>]

On Thu, 17 Aug 2017, Jared McNeill wrote:

> On Thu, 17 Aug 2017, Harold Gutch wrote:
>
> > Oh, does that also apply to the Pi 3 and Zero W then?  I haven't yet
> > felt the need to overclock any of my Raspberries but it would of
> > course be good to know any such caveats.  From what I've read,
> > force_turbo=1 will disable dynamic clocking and make the Raspberry
> > always run on machdep.cpu.frequency.max (I guess) while force_turbo=0
> > will allow it to also run at slower speeds (down to frequency.min?).
> > At least that is how it apparently works in Linux...
>
> I think you're right -- I misunderstood the documentation for how 
> force_turbo=0 applies to the core freq. I'm looking for something I can put 
> in config.txt that will keep core freq at a fixed rate, is applicable to all 
> boards, and doesn't set the warranty bit. Any suggestions?

I checked with the documentation and it jogged my memory: enable_uart=1 is 
what causes core freq to stay consistent. I added force_turbo=0 (default 
value anyway) to config.txt as an example for how to increase the core 
clock speed. As long as enable_uart=1 is set, the core clock will be 
consistent.

Hope this helps,
Jared