I just downloaded and installed the Debian image (on DragonBoard 410C with HDMI 1920x1080), which reports that it's Debian 8.3.
The board boots up, and various software works more-or-less as expected, except that certain video operations are very slow. In particular, when dragging a window around the screen, the window repaint is many cycles and multiple seconds behind the cursor. Indeed, it might take 10 seconds for a window to come to rest after releasing the mouse.
Command 'top' shows process Xorg going close to 100% (of one) CPU during these episodes. Similar behavior for resizing a window, except that in that case the application in question may max out additional CPUs. Chromium for example tries to max out an additional three CPUs.
Anyhow, does this suggest that some aspect of GPU acceleration is not working? Are there settings that need to be enabled? Or is this a known issue?
I did not previously have Debian installed, so I don't have experience with a previous version to compare.