Enable additional driver debugging

configname: CONFIG_DRM_I915_DEBUG

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>drm/i915 Debugging
└─>Enable additional driver debugging
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Choose this option to turn on extra driver debugging that may affect
performance but will catch some internal issues.

Recommended for driver developers only.

If in doubt, say "N".