There are two versions of Debian: Wheezy is mainstream now, and Jessie is the next mainstream release. PWM is not working on Jessie, due to the newer version of Linux.
If you are running Jessie, and would like to get some PWM applications working, Robert Nelson offered a quick, painless way to install to an earlier version of Linux that works with PWM:
sudo apt-get update
sudo apt-get install linux-image-3.8.13-bone67
sudo reboot
After you do this, you’ll get an older version v3.8 of Linux with the capemgr that works. (Robert noted that a mainline solution for Jessie, to 100% replace v3.8 overlays, is still probably a year away.)
For Jessie, i2c/gpio/uart all work fine with v3.14.x However, sometimes you need to enable pinmux/cape - see the following link:
https://github.com/RobertCNelson/dtb-rebuilder/blob/3.14-ti/src/arm/am335x-boneblack.dts
If you want to explore BeagleBoneBlack PWM, here is an easy-to-follow, short video on controlling servos:
I was able to control a couple of PWM servos and a number of GPIO pins using the Dart language. I’ve posted a short 7-second video of the Dart application running on a BeagleBoneBlack that with Jessie, using the older kernel:
I’ve posted a few additional details at the following page:
http://www.dc-computing.com/PWMandGPIOonBeagleBoneUsingDart.html