[Mesa-dev] [PATCH 3/7] mesa/st: support lowering multi-planar YUV

[Rob Clark]

On Thu, Sep 8, 2016 at 5:11 PM, Roland Scheidegger <sroland at vmware.com> wrote:
> Am 08.09.2016 um 22:30 schrieb Rob Clark:
>> Support multi-planar YUV for external EGLImage's (currently just in the
>> dma-buf import path) by lowering to multiple texture fetch's for each
>> plane and CSC in shader.
>>
>> Signed-off-by: Rob Clark <robdclark at gmail.com>
>> ---
>>  src/gallium/auxiliary/util/u_inlines.h      |   4 +-
>>  src/gallium/include/pipe/p_state.h          |   9 +++
>>  src/gallium/include/state_tracker/st_api.h  |   3 +
>>  src/gallium/state_trackers/dri/dri2.c       | 119 +++++++++++++++++++++++-----
>>  src/gallium/state_trackers/dri/dri_screen.c |  11 +++
>>  src/mesa/main/mtypes.h                      |  16 ++++
>>  src/mesa/program/ir_to_mesa.cpp             |   1 +
>>  src/mesa/state_tracker/st_atom_sampler.c    |  41 +++++++++-
>>  src/mesa/state_tracker/st_atom_shader.c     |   3 +
>>  src/mesa/state_tracker/st_atom_texture.c    |  58 ++++++++++++++
>>  src/mesa/state_tracker/st_cb_eglimage.c     |  18 +++++
>>  src/mesa/state_tracker/st_context.c         |   7 +-
>>  src/mesa/state_tracker/st_glsl_to_nir.cpp   |   1 +
>>  src/mesa/state_tracker/st_glsl_to_tgsi.cpp  |   4 +
>>  src/mesa/state_tracker/st_manager.c         |   1 +
>>  src/mesa/state_tracker/st_program.c         |  35 ++++++++
>>  src/mesa/state_tracker/st_program.h         |  37 +++++++++
>>  src/mesa/state_tracker/st_texture.h         |  21 +++++
>>  18 files changed, 362 insertions(+), 27 deletions(-)
>>
>> diff --git a/src/gallium/auxiliary/util/u_inlines.h b/src/gallium/auxiliary/util/u_inlines.h
>> index c2a0b08..b7b8313 100644
>> --- a/src/gallium/auxiliary/util/u_inlines.h
>> +++ b/src/gallium/auxiliary/util/u_inlines.h
>> @@ -136,8 +136,10 @@ pipe_resource_reference(struct pipe_resource **ptr, struct pipe_resource *tex)
>>     struct pipe_resource *old_tex = *ptr;
>>
>>     if (pipe_reference_described(&(*ptr)->reference, &tex->reference,
>> -                                (debug_reference_descriptor)debug_describe_resource))
>> +                                (debug_reference_descriptor)debug_describe_resource)) {
>> +      pipe_resource_reference(&old_tex->next, NULL);
>>        old_tex->screen->resource_destroy(old_tex->screen, old_tex);
>> +   }
>>     *ptr = tex;
>>  }
>>
>> diff --git a/src/gallium/include/pipe/p_state.h b/src/gallium/include/pipe/p_state.h
>> index ebd0337..4a88da6 100644
>> --- a/src/gallium/include/pipe/p_state.h
>> +++ b/src/gallium/include/pipe/p_state.h
>> @@ -498,6 +498,15 @@ struct pipe_resource
>>
>>     unsigned bind;            /**< bitmask of PIPE_BIND_x */
>>     unsigned flags;           /**< bitmask of PIPE_RESOURCE_FLAG_x */
>> +
>> +   /**
>> +    * For planar images, ie. YUV EGLImage external, etc, pointer to the
>> +    * next plane.
>> +    *
>> +    * TODO might be useful for dealing w/ z32s8 too, since at least a
>> +    * couple drivers split these out into separate buffers internally.
>> +    */
>> +   struct pipe_resource *next;
> Would it be possible to stuff the multiple resources somewhere else
> (__DRIImage ?)? Seems a bit of a hack to have resources referencing
> other resources that way.
> (Also, it's odd since things are mostly lowered really outside of
> gallium so it's odd that some of the yuv state still sneaks in there.)

I did originally start down the path of making __DRIImage have
multiple pipe_resource's.. I'm not really sure that would end up
better, and it certainly would be more invasive.

Maybe we should just make that something like 'void *stpriv' to let st
stick whatever it wants in there.  That seems more sane than making
the st use a hashtable to map the rsc back to something else.

One note I would make, is that I think at least both radeon and
freedreno (and maybe others) already do similar things (in driver
backend) for formats like z32_x24s8, since from hw PoV, they are
actually two separate buffers, while from GL and gallium API they are
conceptually a single buffer.  Having a chain of resources, like I did
for planar YUV, seems like a reasonable approach if we ever wanted to
refactor some of that duplicated logic into mesa/st.  (Not that it is
high on my todo list.. just pointing out there are other cases where
we want to treat multiple buffers as one logical buffer.)

BR,
-R