[Mesa-dev] [PATCH 4/6] egl: MESA_image_drm extension

[Jakob Bornecrantz]

Kristian and I discussed this on IRC and I think we got an agreement
on the way forward. I'll inline the comments below in the spec file.

2010/6/4 Kristian Høgsberg <krh at bitplanet.net>:
> ---
>  docs/MESA_image_drm.spec  |  101 +++++++++++++++++++++++++++++++++++++++++++++
>  include/EGL/eglext.h      |   23 ++++++++++
>  src/egl/main/eglapi.c     |   48 +++++++++++++++++++++
>  src/egl/main/eglapi.h     |   10 ++++
>  src/egl/main/eglconfig.c  |    1 +
>  src/egl/main/egldisplay.h |    1 +
>  src/egl/main/eglmisc.c    |    1 +
>  7 files changed, 185 insertions(+), 0 deletions(-)
>  create mode 100644 docs/MESA_image_drm.spec
>
> diff --git a/docs/MESA_image_drm.spec b/docs/MESA_image_drm.spec
> new file mode 100644
> index 0000000..fc0f076
> --- /dev/null
> +++ b/docs/MESA_image_drm.spec
> @@ -0,0 +1,101 @@
> +Name
> +
> +    MESA_image_drm
> +
> +Name Strings
> +
> +    EGL_MESA_image_drm
> +
> +Contact
> +
> +    Kristian Høgsberg <krh at bitplanet.net>
> +
> +Status
> +
> +    Proposal
> +
> +Version
> +
> +    Version 1, June 3, 2010
> +
> +Number
> +
> +    EGL Extension #not assigned
> +
> +Dependencies
> +
> +    Reguires EGL 1.4 or later.  This extension is written against the
> +    wording of the EGL 1.4 specification.
> +
> +    EGL_KHR_base_image is required.
> +
> +Overview
> +
> +    Create EGLImages from DRM buffer handles.
> +
> +IP Status
> +
> +    Open-source; freely implementable.
> +
> +Issues
> +
> +    Nopes
> +
> +New Procedures and Functions
> +
> +    EGLImageKHR eglCreateDRMImageMESA(EGLDisplay dpy,
> +                                      EGLContext ctx,
> +                                      khronos_uint32_t *handle,
> +                                      khronos_uint32_t *stride,
> +                                      const EGLint *attrib_list);

I think we can drop the ctx argument as it is not needed, its only
there on eglCreateImage to know which context to lookup the
ClientBuffer in.

As I outlined in my other mails I think having the handle and stride
arguments on this function so lets move these to eglShareDRMImageMesa
(see more below).

> +
> +    EGLBoolean eglShareDRMImageMESA(EGLDisplay dpy,
> +                                    EGLImageKHR image,
> +                                    khronos_uint32_t *name);

We could rename this function to eglExportDRMImageMesa and let it have
the following arguments.

EGLBoolean eglExportDRMImageMesa(EGLDisplay dpy,
                                  khronos_uint32_t *name,
                                  khronos_uint32_t *handle,
                                  khronos_uint32_t *stride);

Where the either name or handle can be null but not both. The function
will also check against EGL_IMAGE_USE_MESA to make sure that the image
was created with the correct uses.

> +
> +New Tokens
> +
> +    Accepted in the <attrib_list> parameter of eglCreateDRMImageMESA:
> +
> +        EGL_IMAGE_FORMAT_MESA                  0xce01
> +        EGL_IMAGE_USE_MESA                     0xce02
> +
> +    Bits accepted in EGL_IMAGE_USE_MESA:
> +
> +        EGL_IMAGE_USE_SCANOUT_MESA             0x0001
> +        EGL_IMAGE_USE_SHARE_MESA               0x0002
> +
> +    Accepted in the <target> parameter of eglCreateImageKHR:
> +
> +        EGL_DRM_BUFFER_MESA                    0xce03
> +
> +    Use when importing drm buffer:
> +
> +        EGL_IMAGE_NAME_MESA                    0xce04
> +        EGL_IMAGE_STRIDE_MESA                  0xce05
> +
> +    Accepted as values for the EGL_IMAGE_FORMAT_MESA attribute:
> +
> +        EGL_IMAGE_FORMAT_ARGB8888_MESA         0xce06

Hmm since these tokens are for a none generic extension like this
maybe we should make them a bit less generic, maybe sprinkle some DRM
strings in there. Just a thought, could probably stay the same tho.

> +
> +Additions to the EGL 1.4 Specification:
> +
> +    Goes here...
> +
> +    Create drm buffers by calling eglCreateDRMImageMESA, pass
> +    EGL_WIDTH, EGL_EIGHT and format and use in the attrib list using
> +    EGL_IMAGE_FORMAT_MESA and EGL_IMAGE_USE_MESA.  If non-NULL, the
> +    handle (local to the drm fd, for use with KMS) is written to
> +    <handle> and the stride (in bytes) is written to <stride>.
> +
> +    Create a global name for a buffer using eglShareDRMImageMESA.
> +
> +    Import a shared buffer by calling eglCreateImageKHR with
> +    EGL_DRM_BUFFER_MESA as the target, using EGL_WIDTH, EGL_HEIGHT,
> +    EGL_IMAGE_FORMAT_MESA, EGL_IMAGE_NAME_MESA, EGL_IMAGE_STRIDE_MESA
> +    in the attrib list.
> +
> +Revision History
> +
> +    June 3, 2010
> +        Initial draft (Kristian Høgsberg)
> diff --git a/include/EGL/eglext.h b/include/EGL/eglext.h


>-- snip --<

You can probably grab some of the text and tables the extensions in my
patch series for some of the functions.

Cheers Jakob.