[Beignet] Atom 3845

[Rebecca N. Palmer]

That wording implies this is Debian beignet (upstream beignet uses the 
wording "cl_get_gt_device(): error, unknown device: %x"), which is 1.3.0 
in stretch.  This should support Bay Trail, but I don't have the 
hardware to actually try this.

Please post the output of

xrandr --listproviders
glxinfo | grep " vendor\| renderer"
lspci -nn | grep -e "\[03..\]:"

Supported Bay Trail devices have ID [8086:0f31] in the last of these.