the 2D driver initializes MC_FB_LOCATION and related registers sanely
the DRM deduces the layout from these registers
clients use the new SETPARAM ioctl to tell the DRM where they think the
framebuffer is located in the card's address space
the DRM uses all this information to check client state and fix it up if
necessary
This is a prerequisite for things like direct rendering with IGP chips and
video capturing.
pageflipping after a mode switch
take current page into account in AdjustFrame(); writing the CRTC offset
via the CP was probably a bad idea as this can happen asynchronously,
reverted
take frame offset into account when flipping pages
handle CRTC2 as well for pageflipping (untested)
preserve GEN_INT_CNTL on mode switches to prevent interrupts from getting
disabled
ioctl. The DRM reads them from memory addresses the chip writes to on
updates. Fall back to reading the registers directly with an old DRM.
(Tim Smith, cleanups by myself)