[v3,0/3] Add option to mmap GEM buffers cached

Message

Paul Cercueil May 14, 2021, 8:11 p.m. UTC

oRework of my previous patchset which added support for GEM buffers
backed by non-coherent memory to the ingenic-drm driver.

Having GEM buffers backed by non-coherent memory is interesting in
the particular case where it is faster to render to a non-coherent
buffer then sync the data cache, than to render to a write-combine
buffer, and (by extension) much faster than using a shadow buffer.
This is true for instance on some Ingenic SoCs, where even simple
blits (e.g. memcpy) are about three times faster using this method.

For the record, a previous patchset was accepted for 5.10 then had
to be reverted, as it conflicted with some changes made to the DMA API.

The first two patches add support for cached GEM buffers in the DRM
core, the third patch adds support for this functionality in the
ingenic-drm driver for the JZ4770 SoC.

Cheers,
-Paul


Paul Cercueil (3):
  drm: Add support for GEM buffers backed by non-coherent memory
  drm: Add and export function drm_gem_cma_sync_data
  drm/ingenic: Add option to alloc cached GEM buffers

 drivers/gpu/drm/drm_gem_cma_helper.c      | 96 ++++++++++++++++++++++-
 drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 56 ++++++++++++-
 drivers/gpu/drm/ingenic/ingenic-ipu.c     | 18 ++++-
 include/drm/drm_gem_cma_helper.h          | 12 ++-
 4 files changed, 171 insertions(+), 11 deletions(-)