v2: improved swap/MSC-wait scheduling in DPMS-off state

[Ilija Hadzic]

The following patch series is a version 2 of the patches
sent about two weeks ago [1] with the objective to add full
emulation of a running CRTC while the display is in DPMS-off
state. This series addresses the following issues:

1) Fixed an incorrect comment as pointed by Richard Wilbur.
2) Added conditional #define of DRM_CAP_TIMESTAMP_MONOTONIC
   as requested by Michel Dänzer.
3) Fixed two failures of glx-oml-sync-control-waitformsc piglit
   test (last patch, which is new, and patch #7, which existed before
   but is now amended) address the issue (see the commit messages
   for details).
4) Changed the way the last known vblank rate is stored (see commit
   message in patch #5 for details).
5) Simplified a few things (see patch #9 for details)
6) Amended other patches as needed to reconcile them with
   the above changes.

There was a third kind of failure in piglit where test  
glx-oml-sync-control-swapbuffersmsc-return was failing with incorrect
SBC [2]. That problem is outside the scope of this patch series, it existed
before and cannot be fixed with DDX patches. I tracked it all the way
up to DRI2SwapEvent function in DIX and just before DIX calls
WriteEventsToClient (i.e., end of hardware-DDX-DIX path) the SBC is
still correct. Then I tracked it from the top down and got to
dri2XcbSwapBuffers in Mesa (everything below that is generic message
processing code from the server) and SBC is incorrect there. So I think
we are dealing with some ugly corruption of messages between the X server
and the application, which I, admittedly, don't fully understand. However,
what I did proves that it's unrelated to DDX, so it's a topic for a different
thread on a different mailing list.

Hopefully, this patch series addresses all concerns and problems
raised so far.

thanks,

Ilija

[1] http://lists.x.org/archives/xorg-driver-ati/2013-April/024649.html
[2] http://lists.x.org/archives/xorg-driver-ati/2013-May/024677.html