[Mesa-dev] [PATCH 03/10] mesa/st: add endian_format field to struct pipe_resource

[Michel Dänzer]

On 11.04.2016 23:34, Oded Gabbay wrote:
> This patch adds a new field, called "endian_format", to
> "struct pipe_resource". The new field is of type "enum pipe_endian" and
> can receive one of two values:
> - PIPE_ENDIAN_LITTLE
> - PIPE_ENDIAN_NATIVE
> 
> PIPE_ENDIAN_NATIVE is initialized to either PIPE_ENDIAN_LITTLE or
> PIPE_ENDIAN_BIG during build time.
> 
> This field is needed to provide information to the H/W drivers about the
> endianess current state or desired state of the resource. In other words,
> for resources that are the source of the operation, this field indicates
> the resource's current memory layout endianess (big or little endian).
> For resources that are the destination of the operation, this field
> indicates the resource's desired memory layout endianess.
> 
> This field is mandatory because of how mesa works. When we get into the
> H/W driver functions, the driver *ususally* doesn't know if it is doing a
> CPU->GPU, a GPU->CPU, a CPU->CPU or a GPU->GPU operation, as this
> information is "hidden" by the fact we go through common code
> paths (state tracker layer).

That shouldn't matter if the formats are defined completely and their
usage is consistent across the board. Sounds like either or both of
those conditions aren't completely true yet. I agree with Roland that
this should be addressed fundamentally rather than adding more hacks on top.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer