When the vertical blank interrupt is enabled for both pipes, pipe A is
considered primary and pipe B secondary. When it's only enabled for one pipe,
it's always considered primary for backwards compatibility.
(cherry picked from 0c7d7f4361 commit)
Change the fence object interface somewhat to allow some more flexibility.
Make list IOCTLS really restartable.
Try to avoid busy-waits in the kernel using immediate return to user-space with an -EAGAIN.
0x00 EXE fence. Signals when command stream interpreter has reached the point
where the fence was emitted.
0x01 FLUSH fence. Signals when command stream interpreter has reached the point
where the fence was emitted, and all previous drawing operations have been
completed and flushed.
Implements busy wait (for fastest response time / high CPU) and
lazy wait (User interrupt or timer driven).
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.
Michel Dänzer
Thomas Hellstrom
Dave Airlie
Alan Hourihane
Keith Packard
Keith Whitwell
Eric Anholt
Alan Hourihane
Jon Smirl