I am using core so no desktop GUI. I run rtcwake from a script to sleep to memory for a period and then automatically wake. That works. However, it wakes up to a blank screen. I cannot get it to turn the screen back on.
Some PC systems can't currently exit sleep states such as mem using only the kernel code accessed by this driver. They need help from userspace code to make the framebuffer work again.
I have tried video_post. I have tried cat'ing the video card state under /proc/bus/pci/xx/xx.x to a file, sleeping, and cat'ing it back.
xset dpms force on does not work since I am not running x.
Any suggestions for waking up the display or another method for sleep and auto wakeup?