I seem unable to cause any changes to the display by writing to the screen buffer.
This command should fill the screen with random pixels, but the result is shown below with no changes seen.
# cat /dev/urandom > /dev/fb0
cat: write error: No space left on device
The framebuffer variable is set to /dev/fb0, so I am stuck for how to do this.
I have included the result of fbset -i, as it is the most relevant info I could find.
~ fbset -i
mode "1920x1080"
geometry 1920 1080 1920 1080 32
timings 0 0 0 0 0 0 0
accel true
rgba 8/16,8/8,8/0,0/0
endmode
Frame buffer device information:
Name : i915drmfb
Address : (nil)
Size : 8294400
Type : PACKED PIXELS
Visual : TRUECOLOR
XPanStep : 1
YPanStep : 1
YWrapStep : 0
LineLength : 7680
Accelerator : No