[Mesa-dev] [PATCH 0/8] gallium: create a generic way to validate fb params

[Marek Olšák]

Wouldn't it be more flexible for you to just change the depth buffer
format internally by reallocating the depth buffer in the driver
whenever it's incompatible with the colorbuffer? I think you should be
able to do that easily without changing the pipe_resource structure.
If a depth buffer cannot be used by set_framebuffer_state, just create
a new one with an appropriate format, then blit from the old depth
buffer to the new one, so that you won't lose its content, and delete
the old one. For transfers, you just need to blit to convert the depth
buffer to the format the state tracker expects.

I'm quite sure exposing the weird restrictions of your hardware to
applications won't end well. The apps won't like it.

Marek

On Fri, Oct 4, 2013 at 10:34 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> NV30 is blessed with all manners of hardware restrictions. One of them is that
> the render target format's color and depth outputs need to be the same
> bit-ness, i.e. either both 16 or both 32 bits. (In addition to all color
> attachments needing to be the same, and everything needing to be the same
> size.)
>
> There is a PIPE_CAP_MIXED_COLORBUFFER_FORMATS that currently handles the
> requirement of all the cbuf attachments having the same format. This series
> creates a more generic mechanism to perform such validation which allows nv30
> to also check the sizes of the cbuf/zsbuf formats. At the end, I remove that
> PIPE_CAP as it is no longer necessary.
>
> I first tried to use a pipe_framebuffer_state as the parameter to this new
> call, however I couldn't quite figure out how to populate it in case that the
> depth output buffer was a texture (seems to map to a pipe_resource, not a
> pipe_surface).
>
> This series is a follow-up to the discussion started in
> http://lists.freedesktop.org/archives/mesa-dev/2013-September/044658.html
>
> Ilia Mirkin (8):
>   mesa/st: create interface to verify fb format, reject bad fbs
>   gallium: add helper to use as a replacement for the MIXED_COLOR cap
>   i915: hook up is_fb_format_supported
>   r300: hook up is_fb_format_supported
>   softpipe: hook up is_fb_format_supported
>   nv30: hook up is_fb_format_supported
>   gallium: remove PIPE_CAP_MIXED_COLORBUFFER_FORMATS
>   nv30: make sure that cbufs and zsbuf have the same depth
>
>  src/gallium/auxiliary/util/u_format.c            | 20 +++++++++++
>  src/gallium/auxiliary/util/u_format.h            | 11 +++++++
>  src/gallium/docs/source/screen.rst               |  2 --
>  src/gallium/drivers/freedreno/freedreno_screen.c |  1 -
>  src/gallium/drivers/i915/i915_screen.c           |  2 +-
>  src/gallium/drivers/ilo/ilo_screen.c             |  2 --
>  src/gallium/drivers/llvmpipe/lp_screen.c         |  2 --
>  src/gallium/drivers/nouveau/nv30/nv30_screen.c   | 20 ++++++++++-
>  src/gallium/drivers/nouveau/nv50/nv50_screen.c   |  1 -
>  src/gallium/drivers/nouveau/nvc0/nvc0_screen.c   |  1 -
>  src/gallium/drivers/r300/r300_screen.c           |  3 +-
>  src/gallium/drivers/r600/r600_pipe.c             |  1 -
>  src/gallium/drivers/radeonsi/radeonsi_pipe.c     |  1 -
>  src/gallium/drivers/softpipe/sp_screen.c         |  3 +-
>  src/gallium/drivers/svga/svga_screen.c           |  3 --
>  src/gallium/include/pipe/p_defines.h             |  1 -
>  src/gallium/include/pipe/p_screen.h              | 18 +++++++++-
>  src/mesa/state_tracker/st_cb_fbo.c               | 42 ++++++++++++++----------
>  18 files changed, 95 insertions(+), 39 deletions(-)
>
> --
> 1.8.1.5
>
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