[PATCH 0/3] drm/exynos: modify usage of wait for vblank

[Prathyush K]

This patchset fixes a few issues with use of wait for vblank in
exynos drm. 

Please apply these three patches without "drm/exynos: release fb pended by page flip"
patch.

Patch 1: modify wait for vsync functions to use wait queues
This modifies the wait_for_vblank functions to use wait queues
thus ensuring that the current task goes to sleep without taking
up CPU while waiting.

Patch 2: move wait_for_vblank to manager_ops
Currently, we do not call wait for vblank if encoder is in DPMS_OFF
state inside exynos_drm_encoder_complete_scanout function. This is
because wait for vblank is treated as an overlay op. This can be
modified to a manager_op thus removing the above check for DPMS_OFF.
This fixes a crash while removing a fb.
While removing the current fb (crtc->fb == fb) the encoder
dpms off is called and then the framebuffer is removed. So in
this case, the wait for vblank is not called thus leading to a crash
(since fb might get removed before dma is finished)

Patch 3: do not disable crtc if already off
We should not disable the overlay if the crtc is in DPMS_OFF state.
Also, the disable function should not call DPMS_OFF of the crtc.
This is required to ensure we are able to wait for vblank
before freeing any framebuffers after disabling the crtc.

With these three patches and without "drm/exynos: release fb pended by page flip"
I could not find any crash/page_fault in drm with fimd/hdmi during hotplug
and page flips.

Prathyush K (3):
  drm/exynos: modify wait for vsync functions to use wait queues
  drm/exynos: move wait_for_vblank to manager_ops
  drm/exynos: do not disable crtc if already off

 drivers/gpu/drm/exynos/exynos_drm_crtc.c    |    6 +++-
 drivers/gpu/drm/exynos/exynos_drm_drv.h     |   20 ++------------
 drivers/gpu/drm/exynos/exynos_drm_encoder.c |   15 +++--------
 drivers/gpu/drm/exynos/exynos_drm_fimd.c    |   37 ++++++++++++++++++--------
 drivers/gpu/drm/exynos/exynos_drm_hdmi.c    |   22 ++++++++--------
 drivers/gpu/drm/exynos/exynos_drm_hdmi.h    |    2 +-
 drivers/gpu/drm/exynos/exynos_mixer.c       |   37 +++++++++++++++++---------
 7 files changed, 73 insertions(+), 66 deletions(-)