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

[Chia-I Wu]

2010/6/4 Jakob Bornecrantz <wallbraker at gmail.com>:
> 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.
I prefer to sprinkle DRM strings to the tokens.  Stride seems to in bytes now,
where the last version depends on the format(?).  It might be more clear to use
DRM_STRIDE and define the units.

It seems bits-per-pixel is missing here.  Or should it be derived from the
format?

>> +
>> +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.
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