[PATCH v4 0/7] drm: Add fbdev deferred io support to helpers

["Noralf Trønnes" <noralf@tronnes.org>]

This patchset adds fbdev deferred io support to drm_fb_helper and
drm_fb_cma_helper.

It channels fbdev mmap and fb_{write,fillrect,copyarea,imageblit} damage
through the (struct drm_framebuffer_funcs)->dirty callback on the
fb_helper framebuffer which will always run in process context.

I have also added patches that converts qxl and udl to use this
deferred io support. I have only compile tested it, no functional testing.
I know that qxl is purely a software thing so I could actually test it, but
I have never used qemu so I'm not keen on spending a lot of time on that.

This was originally part of the tinydrm patchset.

Changes since v3:
- drm/fb-helper: Add fb_deferred_io support
  - Don't use forward decl, move drm_fb_helper_dirty_work()
  - Use DIV_ROUND_UP in drm_fb_helper_deferred_io()

Changes since v2:
- drm/rect: Add some drm_clip_rect utility functions
  - This patch is dropped
- drm/fb-helper: Add fb_deferred_io support
  - FB_DEFERRED_IO is now always selected by DRM_KMS_FB_HELPER, ifdef removed
  - The drm_clip_rect utility functions are dropped, so open code it
  - docs: use & to denote structs
- drm/qxl: Use drm_fb_helper deferred_io support
  - The drm_clip_rect_{width/height} functions are dropped, so open code it

Changes since v1:
- drm/fb-helper: Add fb_deferred_io support
  - Use a dedicated worker to run the framebuffer flushing like qxl does
  - Add parameter descriptions to drm_fb_helper_deferred_io
- fbdev: fb_defio: Export fb_deferred_io_mmap
  - Expand commit message
- drm/qxl: Use drm_fb_helper deferred_io support
  - Add FIXME about special dirty() callback for fbdev
  - Remove note in commit message about deferred worker, drm_fb_helper
    is similar to qxl now.
- drm/udl: Use drm_fb_helper deferred_io support
  - No need to enable deferred_io by default since drm_fb_helper uses
    a dedicated worker for flushing

Changes since RFC:
- Fix drm_clip_rect use to be exclusive on x2/y2
- Put drm_clip_rect functions in drm_rect.{h,c}
- Take into account that (struct fb_ops *)->fb_{write,...}() can be called
  from atomic context (spin_lock_irqsave)
- Export fb_deferred_io_mmap()
- Add some more documentation
- Add qxl and udl patches

Noralf Trønnes (7):
  drm/udl: Change drm_fb_helper_sys_*() calls to sys_*()
  drm/qxl: Change drm_fb_helper_sys_*() calls to sys_*()
  drm/fb-helper: Add fb_deferred_io support
  fbdev: fb_defio: Export fb_deferred_io_mmap
  drm/fb-cma-helper: Add fb_deferred_io support
  drm/qxl: Use drm_fb_helper deferred_io support
  drm/udl: Use drm_fb_helper deferred_io support

 drivers/gpu/drm/Kconfig             |   1 +
 drivers/gpu/drm/drm_fb_cma_helper.c | 178 ++++++++++++++++++++++++++--
 drivers/gpu/drm/drm_fb_helper.c     | 103 ++++++++++++++++-
 drivers/gpu/drm/qxl/qxl_display.c   |   9 +-
 drivers/gpu/drm/qxl/qxl_drv.h       |   7 +-
 drivers/gpu/drm/qxl/qxl_fb.c        | 223 +++++++++---------------------------
 drivers/gpu/drm/qxl/qxl_kms.c       |   4 -
 drivers/gpu/drm/udl/udl_drv.h       |   2 -
 drivers/gpu/drm/udl/udl_fb.c        | 140 +---------------------
 drivers/video/fbdev/core/fb_defio.c |   3 +-
 include/drm/drm_fb_cma_helper.h     |  14 +++
 include/drm/drm_fb_helper.h         |  15 +++
 include/linux/fb.h                  |   1 +
 13 files changed, 372 insertions(+), 328 deletions(-)

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2.2.2