[PATCH v3 0/5] drm/ast: Place cursor BOs at VRAM high-end

[Thomas Zimmermann]

(was: drm/ast/mgag200: Place cursor BOs at VRAM high-end)

This patchset cleans up the memory management of HW cursors in ast. It
further moves the allocated cursor BOs to the of the video RAM to reduce
memory fragmentation.

The ast driver manages cursor memory in a dedicated GEM VRAM buffer
object. It uses a double-buffering scheme of alternating between offsets
within the GEM BO. The code is convoluted and can lead to memory
fragmentation if the BO is stored the middle of VRAM. This is especially
a problem as ast devices only have a small amount of video memory (e.g.,
8 MiB).

With this patchset, the cursor handling in ast is first split up into
separate functions for copying cursor images, managing buffer objects,
setting scanout addresses, and moving and hiding the cursor. Furthermore,
the driver dedicates a few KiB at the high end of the device's video
memory to storing the cursor's buffer objects. This prevents memory
fragmentation.

The patchset has been tested on ast hardware.

v3:
	* split-off ast patches into separate series
	* move around ast_{show,hide}_cursor in a separate patch
	* fix space-before-tab error near AST_HWC_SIGNATURE_CHECKSUM
v2:
	* remove VRAM buffers in favor of GEM BOs
	* manage BO placement with pin flag


Thomas Zimmermann (5):
  drm/ast: Don't call ast_show_cursor() from ast_cursor_move()
  drm/ast: Move ast_{show,hide}_cursor() within source file
  drm/ast: Move cursor update code to ast_show_cursor()
  drm/ast: Move cursor offset swapping into ast_show_cursor()
  drm/ast: Allocate cursor BOs at high end of video memory

 drivers/gpu/drm/ast/ast_drv.h  |  43 +++---
 drivers/gpu/drm/ast/ast_mode.c | 235 +++++++++++++++++++--------------
 2 files changed, 158 insertions(+), 120 deletions(-)

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2.23.0