Power Management on Angstrom


I am trying to setup a BeagleBone Black with the following features:

  1. Boot directly into a QT embedded application (I am using a 4.3" resistive touchscreen cape).
  2. Good power management features (since this will be embedded and running off battery power).
  3. No software glitches with the touchscreen firmware (cursor jumping around when you click).

This is what I have found so far:

  1. If I install any version of Angstrom, then the normal

echo mem>/sys/power/state

command does not work. This command has also never worked for me with any distribution of Debian. I have tried downloading the TI SDK and booting into Arago.
On Arago, “echo mem>/sys/power/state” will put the BBB into sleep mode, so that’s a win. However, I haven’t figured out a way to get QT apps to run on Arago. Also,
support for Arago seems pretty limited. I can’t even get the opkg repo sources configured correctly.

There also appears to be no firmware support for my touchscreen in Arago. I boot, and the touchscreen remains completely blank. However, I don’t see any desktop
or xwindow service installed. I don’t know how to get one installed though to test to see if the touchscreen would work.

  1. If I install any version of Angstrom after the 06.20.2013 version (https://s3.amazonaws.com/angstrom/demo/beaglebone/BBB-eMMC-flasher-2013.06.20.img.xz),
    then the touchscreen cursor will jump around. As a matter of fact, if I install this version (Angstrom-06.20.2013) and then run

opkg udate && opkg upgrade

Then, as part of that process, it will upgrade the kernel from “kernel - 3.8.13-r23a.22” to “kernel - 3.8.13-r23a.49”. After this upgrade, the touchscreen cursor will glitch and jump around.

Getting to the point:
At this point, I would just be happy if I could get a version of Angstrom that had good power management support and support for my touchscreen. I wouldn’t even care if the cursor jumped around.

I have followed the instructions here “http://wiki.beyondlogic.org/index.php/BeagleBoneBlack_Building_Kernel” and here “http://elinux.org/Building_BBB_Kernel” for building my own kernel, and have
been able to do so successfully. However, I don’t have a lot of experience configuring a kernel or writing patches/modules/etc.

Can anyone help me?

Thank you in advance.

It only works on my debian releases if your using the v3.14.x-ti
kernel (it's totally borked in v3.8.x)