gbm: Add gbm_bo_write entry point

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.

gbm_bo_write() fills that gap while staying out of the efficient
cpu->gpu pixel transfer business.

Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/gbm/main/gbm.h b/src/gbm/main/gbm.h
index cf3d4752c36..af5dc5aee8c 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 *));