XO-1.5 B2. This sounds like #9865.
Made the mistake of NOT disabling suspend the first thing after installing os57. While I was typing on my external USB keyboard, the screen dimmed and before I could react, the power LED went off (in other words, the XO-1,5 went into suspend, with the power LED slowly pulsing); soon the screen went dark. Pressed the power button. The screen briefly "flashed" into visibility, then went dark again (and the power LED went back to pulsing). I was unable to discover anything I could do that would let the screen get back to being usable. Rebooted.
mikus