Created attachment 132261 [details]
Hardware: Dell Venue 8 Pro (5830), board revision 09RP78, BIOS A14 01/28/2016
Software: Kernel 4.12-rc7 (also tested rc5 and rc6) pulled straight from git. Grub bootloader handing off both native resolution and EFI resolution.
Description: LCD panel stays blank after i915 tries to initialize. Backlight is active and I cannot see anything on screen.
Current kernel config and boot log attached
Created attachment 132262 [details]
Created attachment 132270 [details]
Screenshot on "working" DV8P
So after doing some digging I ran across this issue https://bugs.freedesktop.org/show_bug.cgi?id=100356
Having all else fail, I figured I'd try the "hacky" method. Already had drm-tip cloned and compiled, so I just made that one change and recompiled. Installed and added the fastboot to my kernel args. It actually comes up and KMS works. As noted in the issue, an xrandr rotate does kill the output, but mine does show DSI info instead of "UNKNOWN"
I'm going to mark this as a duplicated from 10356, since it seems to be the same problem in the same platform. Thanks for the information.
*** This bug has been marked as a duplicate of bug 100356 ***