[Mesa-dev] [PATCH] gbm: Add a flag to enable creation of rotated scanout buffers (v2)

[Michel Dänzer]

On 05.11.2015 11:32, Vivek Kasireddy wrote:
> For certain platforms that support rotated scanout buffers, currently,
> there is no way to create them with the GBM DRI interface. This flag
> will instruct the DRI driver to create the buffer by setting
> additional requirements such as tiling mode.
> 
> v2: Reserve a bit per angle. (Ville and Michel)
> 
> Cc: Michel Danzer <michel at daenzer.net>
> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy at intel.com>
> ---
>  include/GL/internal/dri_interface.h |  3 +++
>  src/gbm/backends/dri/gbm_dri.c      | 19 +++++++++++++++++--
>  src/gbm/main/gbm.h                  |  7 +++++++
>  3 files changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/include/GL/internal/dri_interface.h b/include/GL/internal/dri_interface.h
> index 6bbd3fa..cd1bf62 100644
> --- a/include/GL/internal/dri_interface.h
> +++ b/include/GL/internal/dri_interface.h
> @@ -1100,6 +1100,9 @@ struct __DRIdri2ExtensionRec {
>  #define __DRI_IMAGE_USE_SCANOUT		0x0002
>  #define __DRI_IMAGE_USE_CURSOR		0x0004 /* Depricated */
>  #define __DRI_IMAGE_USE_LINEAR		0x0008
> +#define __DRI_IMAGE_USE_ROTATION_90	0x0010
> +#define __DRI_IMAGE_USE_ROTATION_180	0x0020
> +#define __DRI_IMAGE_USE_ROTATION_270	0x0040
>  
>  
>  /**

I still think the dri_interface.h change should be a separate patch.


> diff --git a/src/gbm/backends/dri/gbm_dri.c b/src/gbm/backends/dri/gbm_dri.c
> index 57cdeac..a997946 100644
> --- a/src/gbm/backends/dri/gbm_dri.c
> +++ b/src/gbm/backends/dri/gbm_dri.c
> @@ -539,7 +539,8 @@ gbm_dri_is_format_supported(struct gbm_device *gbm,
>        break;
>     case GBM_BO_FORMAT_ARGB8888:
>     case GBM_FORMAT_ARGB8888:
> -      if (usage & GBM_BO_USE_SCANOUT)
> +      if (usage & (GBM_BO_USE_SCANOUT | GBM_BO_USE_ROTATION_90 |
> +          GBM_BO_USE_ROTATION_180 | GBM_BO_USE_ROTATION_270))
>           return 0;
>        break;
>     default:

If you stick to this approach (see below), I suggest adding a
GBM_BO_USE_SCANOUT_ANY define which combines all
GBM_BO_USE_SCANOUT(_ROTATION_*) values, to make these checks less
cumbersome.


> diff --git a/src/gbm/main/gbm.h b/src/gbm/main/gbm.h
> index 8db2153..b200ca6 100644
> --- a/src/gbm/main/gbm.h
> +++ b/src/gbm/main/gbm.h
> @@ -214,6 +214,13 @@ enum gbm_bo_flags {
>      * Buffer is linear, i.e. not tiled.
>      */
>     GBM_BO_USE_LINEAR = (1 << 4),
> +   /**
> +    * Buffer would be rotated and some platforms have additional tiling
> +    * requirements for rotated scanout buffers.
> +    */
> +   GBM_BO_USE_ROTATION_90 = (1 << 5),
> +   GBM_BO_USE_ROTATION_180 = (1 << 6),
> +   GBM_BO_USE_ROTATION_270 = (1 << 7),
>  };
>  
>  int
> 

With this approach, these should be named GBM_BO_USE_SCANOUT_ROTATION_*
to make it clearer that they are alternatives to GBM_BO_USE_SCANOUT.

One issue with this approach is: What happens if several
GBM_BO_USE_SCANOUT_ROTATION_* flags are set, and the hardware has
conflicting requirements for different rotation angles?


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