gbm: Export a getter for per plane handles

v2: Make the error return be -1 instead of 0 because I think 0 is
actually valid.

v3: Set errno to EINVAL when the specified plane is above the total
planes. (Jason Ekstrand)
Return the bo's handle if there is no image ie. for dumb images like cursor (Daniel)

v4:
- Add assertions about plane == 0 (Jason)
- Add a comment about new restriction on planar dumb bo which is not an
earlier patch in the series.
- Correctly refactor from v2 in this patch; it ended up rebased into the
wrong patch.

Signed-off-by: Ben Widawsky <[email protected]>
Reviewed-by: Jason Ekstrand <[email protected]>
Acked-by: Daniel Stone <[email protected]>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/gbm/main/gbm.c b/src/gbm/main/gbm.c
index 37795175644..066ceffc0a3 100644
--- a/src/gbm/main/gbm.c
+++ b/src/gbm/main/gbm.c
@@ -234,6 +234,24 @@ gbm_bo_get_plane_count(struct gbm_bo *bo)
    return bo->gbm->bo_get_planes(bo);
 }
 
+/** Get the handle for the specified plane of the buffer object
+ *
+ * This function gets the handle for any plane associated with the BO. When
+ * dealing with multi-planar formats, or formats which might have implicit
+ * planes based on different underlying hardware it is necessary for the client
+ * to be able to get this information to pass to the DRM.
+ *
+ * \param bo The buffer object
+ * \param plane the plane to get a handle for
+ *
+ * \sa gbm_bo_get_handle()
+ */
+GBM_EXPORT union gbm_bo_handle
+gbm_bo_get_handle_for_plane(struct gbm_bo *bo, int plane)
+{
+   return bo->gbm->bo_get_handle(bo, plane);
+}
+
 /** Write data into the buffer object
  *
  * If the buffer object was created with the GBM_BO_USE_WRITE flag,