[RFC 0/9] nuclear pageflip

Rob Clark rob.clark at linaro.org
Sun Sep 9 20:03:13 PDT 2012

From: Rob Clark <rob at ti.com>

This is following a bit the approach that Ville is taking for atomic-
modeset, in that it is switching over to using properties for everything.
The advantage of this approach is that it makes it easier to add new
attributes to set as part of a page-flip (and even opens the option to
add new object types).

The basic principles are:
 a) split out object state (in this case, plane and crtc, although I
    expect more to be added as atomic-modeset is added) into seperate
    structures that can be atomically commited or rolled back
 b) expand the object property API (set_property()) to take a state
    object.  The obj->set_property() simply updates the state object
    without actually applying the changes to the hw.
 c) after all the property updates are done, the updated state can
    be checked for correctness and against the hw capabilities, and
    then either discarded or committed atomically.

Since we need to include properties in the nuclear-pageflip scheme,
doing everything via properties avoids updating a bunch of additional
driver provided callbacks.  Instead we just drop crtc->page_flip()
and plane->update_plane().  By splitting out the object's mutable
state into drm_{plane,crtc,etc}_state structs (which are wrapped by
the individual drivers to add their own hw specific state), we can
use some helpers (drm_{plane,crtc,etc}_set_property() and
drm_{plane,crtc,etc}_check_state()) to keep core error checking in
drm core and avoid pushing the burden of dealing with common
properties to the individual drivers.

So far, I've only updated omapdrm to the new APIs, as a proof of
concept.  Only a few drivers support drm plane, so I expect the
updates to convert drm-plane to properties should not be so hard.
Possibly for crtc/pageflip we might need to have a transition period
where we still support crtc->page_flip() code path until all drivers
are updated.

My complete branch is here:

  git://github.com/robclark/kernel-omap4.git drm_nuclear

Rob Clark (9):
  drm: add atomic fxns
  drm: add object property type
  drm: add DRM_MODE_PROP_DYNAMIC property flag
  drm: convert plane to properties
  drm: add drm_plane_state
  drm: convert page_flip to properties
  drm: add drm_crtc_state
  drm: nuclear pageflip
  drm/omap: update for atomic age

 drivers/gpu/drm/drm_crtc.c            |  769 +++++++++++++++++++++++----------
 drivers/gpu/drm/drm_crtc_helper.c     |   51 +--
 drivers/gpu/drm/drm_drv.c             |    1 +
 drivers/gpu/drm/drm_fb_helper.c       |   11 +-
 drivers/staging/omapdrm/Makefile      |    1 +
 drivers/staging/omapdrm/omap_atomic.c |  270 ++++++++++++
 drivers/staging/omapdrm/omap_atomic.h |   52 +++
 drivers/staging/omapdrm/omap_crtc.c   |  247 +++++------
 drivers/staging/omapdrm/omap_drv.c    |    5 +
 drivers/staging/omapdrm/omap_drv.h    |   35 +-
 drivers/staging/omapdrm/omap_fb.c     |   44 +-
 drivers/staging/omapdrm/omap_plane.c  |  270 ++++++------
 include/drm/drm.h                     |    2 +
 include/drm/drmP.h                    |   32 ++
 include/drm/drm_crtc.h                |  140 ++++--
 include/drm/drm_mode.h                |   48 ++
 16 files changed, 1378 insertions(+), 600 deletions(-)
 create mode 100644 drivers/staging/omapdrm/omap_atomic.c
 create mode 100644 drivers/staging/omapdrm/omap_atomic.h


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