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, 19 insertions, 0 deletions

diff --git a/src/gbm/main/gbm.c b/src/gbm/main/gbm.c
index 987e96500f8..3994f86aafc 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