[Intel-gfx] CONFIG_DRM_FBDEV_OVERALLOC seems to have no effect.

[Michael T. Kloos]

There seems to be a difference in behavior of CONFIG_DRM_FBDEV_OVERALLOC 
a.k.a. drm_kms_helper.drm_fbdev_overalloc (cmdline param) between my 
NOUVEAU system and my i915 system.  On my NOUVEAU system, specifying 
drm_kms_helper.drm_fbdev_overalloc=200 (as opposed to the default of 
100) doubles the yres_virtual resolution as reported by fbset or the 
ioctl FBIOGET_VSCREENINFO.  However, on my i915 systems, no effect is 
observed.  I would be surprised if I've managed to stumble across an 
actual kernel bug, but since these features are relatively new, I 
figured I'd ask about it.