Add support for GTT based scrolling. Instead of pushing bits around we simply
use the GTT to change the mappings. This provides us with a very fast way to
scroll the display providing we have enough memory to allocate on 4K line
boundaries. In practice this seems to be the case except for very big displays
such as HDMI, and the usual configurations are netbooks/tablets.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This isn't actually usable - we simply don't have the vmap space on a 32bit
system to do this stunt. Instead we will rely on the low level drivers
limiting the console resolution as before.
The real fix is for someone to write a page table aware version of the
framebuffer console blit functions. Good university student project
perhaps..
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
We support 2D acceleration on some devices but we try and do tricks with
the GTT as a starting point as this is far faster. The GTT logic could be
improved further but for most display sizes it already makes a pretty good
decision.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
