Grab the base index when allocating buffers and mapping them

Because there might be more than a single call to CreateSurfaces,
we cannot assume that the index relative to the number of surfaces
requested in a single call matches the v4l2 index.

Grab the base index (as returned by the kernel) when allocating
buffers and use it for memory mapping and addressing them in v4l2.
This avoids memory-mapping the first (index 0) buffer multiple times
in that scenario instead of the n-th allocated buffer (in the n-th
call in the sequence).

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>

src/context.c

@@ -57,6 +57,8 @@ VAStatus RequestCreateContext(VADriverContextP context, VAConfigID config_id,
 	VAContextID id;
 	VAStatus status;
 	unsigned int pixelformat;
+	unsigned int index_base;
+	unsigned int index;
 	unsigned int i;
 	int rc;
 
@@ -103,7 +105,7 @@ VAStatus RequestCreateContext(VADriverContextP context, VAConfigID config_id,
 
 	rc = v4l2_create_buffers(driver_data->video_fd,
 				 V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE,
-				 surfaces_count);
+				 surfaces_count, &index_base);
 	if (rc < 0) {
 		status = VA_STATUS_ERROR_ALLOCATION_FAILED;
 		goto error;
@@ -123,6 +125,8 @@ VAStatus RequestCreateContext(VADriverContextP context, VAConfigID config_id,
 	memcpy(ids, surfaces_ids, surfaces_count * sizeof(VASurfaceID));
 
 	for (i = 0; i < surfaces_count; i++) {
+		index = index_base + i;
+
 		surface_object = SURFACE(driver_data, surfaces_ids[i]);
 		if (surface_object == NULL) {
 			status = VA_STATUS_ERROR_INVALID_SURFACE;
@@ -130,7 +134,7 @@ VAStatus RequestCreateContext(VADriverContextP context, VAConfigID config_id,
 		}
 
 		rc = v4l2_query_buffer(driver_data->video_fd,
-				       V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, i,
+				       V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, index,
 				       &length, &offset, 1);
 		if (rc < 0) {
 			status = VA_STATUS_ERROR_ALLOCATION_FAILED;
@@ -144,8 +148,7 @@ VAStatus RequestCreateContext(VADriverContextP context, VAConfigID config_id,
 			goto error;
 		}
 
-		surface_object->source_index = i;
+		surface_object->source_index = index;
-		surface_object->destination_index = i;
 		surface_object->source_data = source_data;
 		surface_object->source_size = length;
 	}

src/surface.c

@@ -58,6 +58,8 @@ VAStatus RequestCreateSurfaces2(VADriverContextP context, unsigned int format,
 	unsigned int destination_sizes[VIDEO_MAX_PLANES];
 	unsigned int destination_bytesperlines[VIDEO_MAX_PLANES];
 	unsigned int destination_planes_count;
+	unsigned int index_base;
+	unsigned int index;
 	unsigned int i, j;
 	VASurfaceID id;
 	bool found;
@@ -93,18 +95,21 @@ VAStatus RequestCreateSurfaces2(VADriverContextP context, unsigned int format,
 
 	rc = v4l2_create_buffers(driver_data->video_fd,
 				 V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE,
-				 surfaces_count);
+				 surfaces_count, &index_base);
 	if (rc < 0)
 		return VA_STATUS_ERROR_ALLOCATION_FAILED;
 
 	for (i = 0; i < surfaces_count; i++) {
+		index = index_base + i;
+
 		id = object_heap_allocate(&driver_data->surface_heap);
 		surface_object = SURFACE(driver_data, id);
 		if (surface_object == NULL)
 			return VA_STATUS_ERROR_ALLOCATION_FAILED;
 
 		rc = v4l2_query_buffer(driver_data->video_fd,
-				       V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE, i,
+				       V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE,
+				       index,
 				       surface_object->destination_map_lengths,
 				       surface_object->destination_map_offsets,
 				       video_format->v4l2_buffers_count);
@@ -157,7 +162,7 @@ VAStatus RequestCreateSurfaces2(VADriverContextP context, unsigned int format,
 		surface_object->source_data = NULL;
 		surface_object->source_size = 0;
 
-		surface_object->destination_index = 0;
+		surface_object->destination_index = index;
 
 		surface_object->destination_planes_count =
 			destination_planes_count;

src/v4l2.c

@@ -126,7 +126,7 @@ int v4l2_get_format(int video_fd, unsigned int type, unsigned int *width,
 }
 
 int v4l2_create_buffers(int video_fd, unsigned int type,
-			unsigned int buffers_count)
+			unsigned int buffers_count, unsigned int *index_base)
 {
 	struct v4l2_create_buffers buffers;
 	int rc;
@@ -150,6 +150,9 @@ int v4l2_create_buffers(int video_fd, unsigned int type,
 		return -1;
 	}
 
+	if (index_base != NULL)
+		*index_base = buffers.index;
+
 	return 0;
 }
 

src/v4l2.h

@@ -37,7 +37,7 @@ int v4l2_get_format(int video_fd, unsigned int type, unsigned int *width,
 		    unsigned int *height, unsigned int *bytesperline,
 		    unsigned int *sizes, unsigned int *planes_count);
 int v4l2_create_buffers(int video_fd, unsigned int type,
-			unsigned int buffers_count);
+			unsigned int buffers_count, unsigned int *index_base);
 int v4l2_query_buffer(int video_fd, unsigned int type, unsigned int index,
 		      unsigned int *lengths, unsigned int *offsets,
 		      unsigned int buffers_count);