Created attachment 199791 [details] Log with drm.debug=14 on kernel command line. I'm trying to configure Ubuntu 15.10 on HP Pro Tablet 408 G1 (P/N: L3S95AA#ACB if anyone interested). It is based on Z3736F. Currently I'm stuck with problem in i915. It can't determine PLL divider (?). With nomodeset I can get to desktop and then xrandr reports this mode: 800 x 1280 (0x26e) 78.848MHz / 98.56kHz / 77 Hz. In the dmesg.log you can see modified '[drm:vlv_get_dsi_pclk [i915]] *ERROR* wrong m_seed programmed' message, because I thought I could get something useful out of pll_div value. :) Obviously, this was wrong.
BTW, I've got picture on LCD connected to HDMI. 'Displays' applet showed both screens active with native resolution set, but tablet's screen was black. Will it help if I attach log for booting in such configuration? What debug level should I set?
Please file new i915 bugs at the freedesktop.org bugzilla https://bugs.freedesktop.org/enter_bug.cgi?product=DRI&component=DRM/Intel
Ok. Here is the link if anyone wants to follow: https://bugs.freedesktop.org/show_bug.cgi?id=93744