State of i915/drm/kms support

[Francois Tigeot]

The old DRM subsystem and i915 drivers have been replaced by much more
recent versions in -master, more or less equivalent to what is present
in Linux 3.4-3.5.

It is possible to use Intel graphics with GPUs as recent as the Ivy-Bridge
generation (Xeons 1200 v2, third generation Core i3/i5/i7 CPUs).

Some work has been done in the base system and in dports so that Xorg
can be used out of the box by just running startx.


A few caveats apply and will most likely still be true for DragonFly 3.6:

- There is no Haswell support, Xeons E3-1200 v3 and Core i-something 4000
  CPUs cannot display graphics with this driver (yet)

- Once the primary display is put into graphic mode by Xorg, it is never
  switched back to the old 80x25 VGA text mode. Virtual terminals thus
  become unusable
  Typing commands blindly after is possible but not very useful.

- KMS graphics support is only usable out of the box on 64-bit systems,
  the new kernel drivers have their own memory managers and require
  advanced virtual memory functions the i386 kernel is not able to provide.


The last point is not an issue for legacy 32-bit only machines: old Xorg
versions are used by default on DragonFly/i386 and are able to manage Intel
GPUs up to at least the "GEN4" generation of chipsets, which was present on
early Core 2 systems (already amd64-compatible).

All Intel GPUs requiring the new i915/kms driver are associated with 64-bit
processors and DragonFly/x86_64 can be used on these machines.

-- 
Francois Tigeot