i915 vblanks can be generated from either pipe a or b, however a disabled
pipe generates no interrupts. This change allows the X server to select
which pipe generates vblank interrupts.
that particular file. Its contents have changed a good bit since the
original sis code, and the original sis code didn't care much about
attribution since it routinely disclaims Precision Insight/VA Linux
from responsibility. Also, adjust formatting around license headers
(have a comment open immediately before the "Copyright" line, not as a
runon of any previous comments) for automatic processing into FreeBSD,
where /*- is used to signal the beginning of license headers for
automatic compilation of license lists.
Thomas Hellstrom
Dave Airlie
Alan Hourihane
Keith Packard
Alan Hourihane
Eric Anholt
Jon Smirl
Keith Whitwell