[RFC 0/3] drm/gem: Add drm_gem_object_funcs

Daniel Vetter daniel at ffwll.ch
Sat Sep 22 10:04:02 UTC 2018


On Fri, Sep 21, 2018 at 06:42:27PM +0200, Noralf Trønnes wrote:
> Hi,
> 
> I've found it odd that the GEM object has its callbacks on drm_driver
> and not a vtable of its own. But something being odd isn't enough to
> make a change (me thinks).
> 
> After working on the GEM shmem helper I saw that a few drivers have
> runtime support for 2 memory types for their buffers (shmem,vram,cma).
> I have realised that if the shmem helper was self contained wrt the
> callbacks, it would be easier for these types of drivers to use the
> helper. All they needed to do was to determine the buffer type on GEM
> object creation time and let the helper handle the rest of the
> callbacks.
> 
> No sure if this makes sense or if the approach is to simplistic. Hence
> the RFC.
> 
> I've added a patch to give an example of how this would look for the CMA
> helper and vc4 (I'm not volunteering to refactor the CMA helper and
> drivers).

I very much like, the drm_driver dumping ground has been a sore spot for
me for a long time, and the per-object callback structures look so much
nicer in kms. That's why I also really liked moving all the vblank stuff
from drm_driver to the drm_crtc_(helper_)funcs struct.

Cheers, Daniel
> 
> Noralf.
> 
> Noralf Trønnes (3):
>   drm/driver: Add defaults for .gem_prime_export/import callbacks
>   drm/gem: Add drm_gem_object_funcs
>   drm/cma: Use drm_gem_object_funcs
> 
>  Documentation/gpu/todo.rst           |   7 ++
>  drivers/gpu/drm/drm_client.c         |  12 ++-
>  drivers/gpu/drm/drm_fb_helper.c      |   8 +-
>  drivers/gpu/drm/drm_gem.c            | 108 +++++++++++++++++++++++++--
>  drivers/gpu/drm/drm_gem_cma_helper.c |  99 +++++++++----------------
>  drivers/gpu/drm/drm_prime.c          |  50 +++++++------
>  drivers/gpu/drm/vc4/vc4_bo.c         |  46 ++++++------
>  drivers/gpu/drm/vc4/vc4_drv.c        |  26 +------
>  drivers/gpu/drm/vc4/vc4_drv.h        |   6 +-
>  include/drm/drm_drv.h                |   4 +
>  include/drm/drm_gem.h                | 138 +++++++++++++++++++++++++++++++++++
>  include/drm/drm_gem_cma_helper.h     |  17 +----
>  12 files changed, 350 insertions(+), 171 deletions(-)
> 
> -- 
> 2.15.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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