[v4,0/4] drm/vkms: add overlay plane support

Message

Melissa Wen April 24, 2021, 8:22 a.m. UTC

Adding support to overlay type in addition to primary and cursor plane.
The planes composition relies on the z order of the active planes and
only occurs if there is a primary plane (as in the current behavior).

The first patch switches the function of initializing planes from
drm_universal_plane_init to drmm_universal_plane_alloc. It aims to
improve aspects of allocation and cleanup operations, leaving it to the
DRM infrastructure.

The second patch generalizes variables and functions names to refer to
any kind of plane, not only cursor. The goal is to reuse them for
blending overlay and cursor planes to primary.

The third patch enables the plane composition to select a pixel blend
operation according to the plane format (XRGB8888 or ARGB8888).

The last patch creates a module option to enable overlay, and includes
overlay to supported types of plane. When the overlay option is enabled,
one overlay plane is initialized (plus primary and cursor) and it is
included in the planes composition.

This work preserves the current results of IGT tests: kms_cursor_crc;
kms_flip and kms_writeback. In addition, subtests related to overlay in
kms_atomic and kms_plane_cursor start to pass (pointed out in the commit
message).

v2:

- Drop unnecessary changes that init crtc without cursor (Daniel)
- Replace function to initialize planes (Daniel)
- Add proper pixel blending op according to the plane format (Daniel)

v3:

- Proper use of the variable funcs (kernel bot)
- Adjust the patch series format

v4:
- use better names for functions of plane composition (Daniel)
- clear alpha channel (0xff) after blend color values by pixel
- improve comments on blend ops to reflect the current state
- describe in the commit message future improvements for plane composition

Melissa Wen (4):
  drm/vkms: init plane using drmm_universal_plane_alloc
  drm/vkms: rename cursor to plane on ops of planes composition
  drm/vkms: add XRGB planes composition
  drm/vkms: add overlay support

 drivers/gpu/drm/vkms/vkms_composer.c | 104 ++++++++++++++++++---------
 drivers/gpu/drm/vkms/vkms_drv.c      |   5 ++
 drivers/gpu/drm/vkms/vkms_drv.h      |   9 ++-
 drivers/gpu/drm/vkms/vkms_output.c   |  28 ++++----
 drivers/gpu/drm/vkms/vkms_plane.c    |  51 ++++++-------
 5 files changed, 125 insertions(+), 72 deletions(-)