Sansa AMS v1/v2 Power Saving W/ menu clipv1/2, clip+ zip, fuzev1/2, e/c200v2

[Bilgus]

There have been quite a few issues across the SANSA AMS line related
to CPU undervolting while most players show greatly increased runtime
some crash.
Rather than constantly upping the voltage we now have a
setting with a safe value for all players and the option for lower voltages

In addition there are options to underclock I2C, Disk, (V2 Display)

So far we have a report of ~50% runtime increase over stock on the fuzev1
I have a clip+ that increased 40% and thats about all the runtime testing so far..
its been run on clip+, zip, fuzev1 but other ams players are supported ( c200v2, e200v2, fuzev2, clipv1..)

There are a few changes to the debug menu, more clocks are shown and the home button scrolls the
menu to the left so you clipzip users can read the values (center button or skipping to next screen resets the position)

Do Note: this is a WIP, some settings might cause undesired results on some devices ( let me know )

Gerrit patch:
http://gerrit.rockbox.org/r/#/c/1737/


Included are builds for Clip v1/2, Clip+, Clip zip, fuze v1/2, c200v2, e200v2

https://www.mediafire.com/folder/i1mw99rkf5ex2/AMS_Powersave

[cereal_killer]

I'd like to test this on my fuze+ (or is this not an AMS device?). Any chance for such a build?
Thanks.

[Bilgus]

fuze+ is the imx233 there are options for power saving there but I haven't messed with it as of yet

[saratoga]

I haven't had a chance to try this, but it sounds useful for debugging. Are the defaults the same as the current Dev build?

[Bilgus]

it actually defaults to higher voltages unless set otherwise but your current cfg file from a dev build should work fine

[saratoga]

The display power save options seems to glitch the screen occasionally for me on the Clip Zip (very slow redraw then it stops updating for a few seconds before resuming).  At least I think that is the screen power save option.

[Bilgus]

Yeah that sounds like the screen power save option, really upon testing with an ammeter I was able to achieve greater savings by tweaking the display routines on the clip+ than slowing down the refresh of the screen and I imagine it is similar on the clipzip but it has a different screen and display controller so I haven't looked into it yet but its On My List (TM) :p

[saratoga]

I think you can commit the debug menu improvements.  They seem generally nice to have.