[Mesa-dev] [PATCH] gbm: Add gbm_bo_write entry point

Mandeep Baines mandeep.baines at gmail.com
Thu May 3 14:08:55 PDT 2012


2012/5/2 Kristian Høgsberg <krh at bitplanet.net>:
> This new gbm entry point allows writing data into a gbm bo.  The bo has
> to be created with the GBM_BO_USE_WRITE flag, and it's only required to
> work for GBM_BO_USE_CURSOR_64X64 bos.
>
> The gbm API is designed to be the glue layer between EGL and KMS, but there
> was never a mechanism initialize a buffer suitable for use with KMS
> hw cursors.  The hw cursor bo is typically not compatible with anything EGL
> can render to, and thus there's no way to get data into such a bo.
>

Hi Kristian,

What is the advantage of this approach over just using dumb buffers
via DRM_IOCTL_MODE_CREATE_DUMB and
DRM_IOCTL_MODE_MAP_DUMB?

Regards,
Mandeep

> gbm_bo_write() fills that gap while staying out of the efficient
> cpu->gpu pixel transfer business.
> ---
>  include/GL/internal/dri_interface.h       |   10 +++++++++-
>  src/gbm/backends/dri/gbm_dri.c            |   18 ++++++++++++++++++
>  src/gbm/main/gbm.c                        |   19 +++++++++++++++++++
>  src/gbm/main/gbm.h                        |    9 +++++++++
>  src/gbm/main/gbmint.h                     |    1 +
>  src/mesa/drivers/dri/intel/intel_screen.c |   24 ++++++++++++++++++++++--
>  6 files changed, 78 insertions(+), 3 deletions(-)
>
> diff --git a/include/GL/internal/dri_interface.h b/include/GL/internal/dri_interface.h
> index eafbe10..e37917e 100644
> --- a/include/GL/internal/dri_interface.h
> +++ b/include/GL/internal/dri_interface.h
> @@ -894,7 +894,7 @@ struct __DRIdri2ExtensionRec {
>  * extensions.
>  */
>  #define __DRI_IMAGE "DRI_IMAGE"
> -#define __DRI_IMAGE_VERSION 3
> +#define __DRI_IMAGE_VERSION 4
>
>  /**
>  * These formats correspond to the similarly named MESA_FORMAT_*
> @@ -911,6 +911,7 @@ struct __DRIdri2ExtensionRec {
>  #define __DRI_IMAGE_USE_SHARE          0x0001
>  #define __DRI_IMAGE_USE_SCANOUT                0x0002
>  #define __DRI_IMAGE_USE_CURSOR         0x0004
> +#define __DRI_IMAGE_USE_WRITE          0x0008
>
>  /**
>  * queryImage attributes
> @@ -955,6 +956,13 @@ struct __DRIimageExtensionRec {
>     * \since 2
>     */
>    GLboolean (*validateUsage)(__DRIimage *image, unsigned int use);
> +
> +   /**
> +    * Write data into image.
> +    *
> +    * \since 4
> +    */
> +   int (*write)(__DRIimage *image, const void *buf, size_t count);
>  };
>
>
> diff --git a/src/gbm/backends/dri/gbm_dri.c b/src/gbm/backends/dri/gbm_dri.c
> index 4df6e8f..e5ddfb6 100644
> --- a/src/gbm/backends/dri/gbm_dri.c
> +++ b/src/gbm/backends/dri/gbm_dri.c
> @@ -291,6 +291,18 @@ gbm_dri_is_format_supported(struct gbm_device *gbm,
>    return 1;
>  }
>
> +static int
> +gbm_dri_bo_write(struct gbm_bo *_bo, const void *buf, size_t count)
> +{
> +   struct gbm_dri_device *dri = gbm_dri_device(_bo->gbm);
> +   struct gbm_dri_bo *bo = gbm_dri_bo(_bo);
> +
> +   if (dri->image->base.version < 4)
> +      return -1;
> +
> +   return dri->image->write(bo->image, buf, count);
> +}
> +
>  static void
>  gbm_dri_bo_destroy(struct gbm_bo *_bo)
>  {
> @@ -390,6 +402,9 @@ gbm_dri_bo_create(struct gbm_device *gbm,
>    int dri_format;
>    unsigned dri_use = 0;
>
> +   if (dri->image->base.version < 4 && (usage & GBM_BO_USE_WRITE))
> +      return NULL;
> +
>    bo = calloc(1, sizeof *bo);
>    if (bo == NULL)
>       return NULL;
> @@ -421,6 +436,8 @@ gbm_dri_bo_create(struct gbm_device *gbm,
>       dri_use |= __DRI_IMAGE_USE_SCANOUT;
>    if (usage & GBM_BO_USE_CURSOR_64X64)
>       dri_use |= __DRI_IMAGE_USE_CURSOR;
> +   if (usage & GBM_BO_USE_WRITE)
> +      dri_use |= __DRI_IMAGE_USE_WRITE;
>
>    bo->image =
>       dri->image->createImage(dri->screen,
> @@ -491,6 +508,7 @@ dri_device_create(int fd)
>    dri->base.base.bo_create = gbm_dri_bo_create;
>    dri->base.base.bo_create_from_egl_image = gbm_dri_bo_create_from_egl_image;
>    dri->base.base.is_format_supported = gbm_dri_is_format_supported;
> +   dri->base.base.bo_write = gbm_dri_bo_write;
>    dri->base.base.bo_destroy = gbm_dri_bo_destroy;
>    dri->base.base.destroy = dri_destroy;
>    dri->base.base.surface_create = gbm_dri_surface_create;
> diff --git a/src/gbm/main/gbm.c b/src/gbm/main/gbm.c
> index 987e965..3994f86 100644
> --- a/src/gbm/main/gbm.c
> +++ b/src/gbm/main/gbm.c
> @@ -231,6 +231,25 @@ gbm_bo_get_handle(struct gbm_bo *bo)
>    return bo->handle;
>  }
>
> +/** Write data into the buffer object
> + *
> + * If the buffer object was created with the GBM_BO_USE_WRITE flag,
> + * this function can used to write data into the buffer object.  The
> + * data is copied directly into the object and it's the responsiblity
> + * of the caller to make sure the data represents valid pixel data,
> + * according to the width, height, stride and format of the buffer object.
> + *
> + * \param bo The buffer object
> + * \param buf The data to write
> + * \param count The number of bytes to write
> + * \return Returns -1 on error, 0 otherwise
> + */
> +GBM_EXPORT int
> +gbm_bo_write(struct gbm_bo *bo, const void *buf, size_t count)
> +{
> +   return bo->gbm->bo_write(bo, buf, count);
> +}
> +
>  /** Get the gbm device used to create the buffer object
>  *
>  * \param bo The buffer object
> diff --git a/src/gbm/main/gbm.h b/src/gbm/main/gbm.h
> index cf3d475..af5dc5a 100644
> --- a/src/gbm/main/gbm.h
> +++ b/src/gbm/main/gbm.h
> @@ -201,6 +201,12 @@ enum gbm_bo_flags {
>     * as the storage for a color buffer
>     */
>    GBM_BO_USE_RENDERING    = (1 << 2),
> +   /**
> +    * Buffer can be used for gbm_bo_write.  This is guaranteed to work
> +    * with GBM_BO_USE_CURSOR_64X64. but may not work for other
> +    * combinations.
> +    */
> +   GBM_BO_USE_WRITE    = (1 << 3),
>  };
>
>  int
> @@ -248,6 +254,9 @@ gbm_bo_get_device(struct gbm_bo *bo);
>  union gbm_bo_handle
>  gbm_bo_get_handle(struct gbm_bo *bo);
>
> +int
> +gbm_bo_write(struct gbm_bo *bo, const void *buf, size_t count);
> +
>  void
>  gbm_bo_set_user_data(struct gbm_bo *bo, void *data,
>                     void (*destroy_user_data)(struct gbm_bo *, void *));
> diff --git a/src/gbm/main/gbmint.h b/src/gbm/main/gbmint.h
> index 0e98bdf..8eb8671 100644
> --- a/src/gbm/main/gbmint.h
> +++ b/src/gbm/main/gbmint.h
> @@ -70,6 +70,7 @@ struct gbm_device {
>                                               void *egl_dpy, void *egl_img,
>                                               uint32_t width, uint32_t height,
>                                               uint32_t usage);
> +   int (*bo_write)(struct gbm_bo *bo, const void *buf, size_t data);
>    void (*bo_destroy)(struct gbm_bo *bo);
>
>    struct gbm_surface *(*surface_create)(struct gbm_device *gbm,
> diff --git a/src/mesa/drivers/dri/intel/intel_screen.c b/src/mesa/drivers/dri/intel/intel_screen.c
> index 9db5606..e945d14 100644
> --- a/src/mesa/drivers/dri/intel/intel_screen.c
> +++ b/src/mesa/drivers/dri/intel/intel_screen.c
> @@ -305,6 +305,11 @@ intel_create_image(__DRIscreen *screen,
>       tiling = I915_TILING_NONE;
>    }
>
> +   /* We only support write for cursor drm images */
> +   if ((use & __DRI_IMAGE_USE_WRITE) &&
> +       use != (__DRI_IMAGE_USE_WRITE | __DRI_IMAGE_USE_CURSOR))
> +      return NULL;
> +
>    image = CALLOC(sizeof *image);
>    if (image == NULL)
>       return NULL;
> @@ -411,15 +416,30 @@ intel_validate_usage(__DRIimage *image, unsigned int use)
>    return GL_TRUE;
>  }
>
> +static int
> +intel_image_write(__DRIimage *image, const void *buf, size_t count)
> +{
> +   if (image->region->map_refcount)
> +      return -1;
> +   /* if use != WRITE || region->map_refcount; return -1; */
> +
> +   drm_intel_bo_map(image->region->bo, true);
> +   memcpy(image->region->bo->virtual, buf, count);
> +   drm_intel_bo_unmap(image->region->bo);
> +
> +   return 0;
> +}
> +
>  static struct __DRIimageExtensionRec intelImageExtension = {
> -    { __DRI_IMAGE, 3 },
> +    { __DRI_IMAGE, 4 },
>     intel_create_image_from_name,
>     intel_create_image_from_renderbuffer,
>     intel_destroy_image,
>     intel_create_image,
>     intel_query_image,
>     intel_dup_image,
> -    intel_validate_usage
> +    intel_validate_usage,
> +    intel_image_write
>  };
>
>  static const __DRIextension *intelScreenExtensions[] = {
> --
> 1.7.10
>
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