On (20/02/04 11:56), Sergey Senozhatsky wrote:
> +static void set_buffer_cache_hints(struct vb2_queue *q,
> + struct vb2_buffer *vb,
> + struct v4l2_buffer *b)
> +{
> + /*
> + * DMA exporter should take care of cache syncs, so we can avoid
> + * explicit ->prepare()/->finish() syncs. For other ->memory types
> + * we always need ->prepare() or/and ->finish() cache sync.
> + */
> + if (q->memory == VB2_MEMORY_DMABUF) {
> + vb->need_cache_sync_on_finish = 0;
> + vb->need_cache_sync_on_prepare = 0;
> + return;
> + }
> +
> + if (!q->allow_cache_hints)
> + return;
> +
> + vb->need_cache_sync_on_prepare = 1;
> + /*
> + * ->finish() cache sync can be avoided when queue direction is
> + * TO_DEVICE.
> + */
> + if (q->dma_dir != DMA_TO_DEVICE)
> + vb->need_cache_sync_on_finish = 1;
> + else
> + vb->need_cache_sync_on_finish = 0;
> +
> + if (b->flags & V4L2_BUF_FLAG_NO_CACHE_INVALIDATE)
> + vb->need_cache_sync_on_finish = 0;
> +
> + if (b->flags & V4L2_BUF_FLAG_NO_CACHE_CLEAN)
> + vb->need_cache_sync_on_prepare = 0;
> +}
Last minute changes (tm), sorry. This is not right.
====8<====8<====
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: [PATCH] videobuf2: handle V4L2 buffer cache flags
Set video buffer cache management flags corresponding to V4L2 cache
flags.
Both ->prepare() and ->finish() cache management hints should be
passed during this stage (buffer preparation), because there is no
other way for user-space to skip ->finish() cache flush.
There are two possible alternative approaches:
- The first one is to move cache sync from ->finish() to dqbuf().
But this breaks some drivers, that need to fix-up buffers before
dequeueing them.
- The second one is to move ->finish() call from ->done() to dqbuf.
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
---
.../media/common/videobuf2/videobuf2-v4l2.c | 36 +++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index eb5d5db96552..8ef57496b34a 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -337,6 +337,41 @@ static int vb2_fill_vb2_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b
return 0;
}
+static void set_buffer_cache_hints(struct vb2_queue *q,
+ struct vb2_buffer *vb,
+ struct v4l2_buffer *b)
+{
+ /*
+ * DMA exporter should take care of cache syncs, so we can avoid
+ * explicit ->prepare()/->finish() syncs. For other ->memory types
+ * we always need ->prepare() or/and ->finish() cache sync.
+ */
+ if (q->memory == VB2_MEMORY_DMABUF) {
+ vb->need_cache_sync_on_finish = 0;
+ vb->need_cache_sync_on_prepare = 0;
+ return;
+ }
+
+ vb->need_cache_sync_on_prepare = 1;
+ vb->need_cache_sync_on_finish = 1;
+
+ if (!q->allow_cache_hints)
+ return;
+
+ /*
+ * ->finish() cache sync can be avoided when queue direction is
+ * TO_DEVICE.
+ */
+ if (q->dma_dir == DMA_TO_DEVICE)
+ vb->need_cache_sync_on_finish = 0;
+
+ if (b->flags & V4L2_BUF_FLAG_NO_CACHE_INVALIDATE)
+ vb->need_cache_sync_on_finish = 0;
+
+ if (b->flags & V4L2_BUF_FLAG_NO_CACHE_CLEAN)
+ vb->need_cache_sync_on_prepare = 0;
+}
+
static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
struct v4l2_buffer *b, bool is_prepare,
struct media_request **p_req)
@@ -381,6 +416,7 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *md
}
if (!vb->prepared) {
+ set_buffer_cache_hints(q, vb, b);
/* Copy relevant information provided by the userspace */
memset(vbuf->planes, 0,
sizeof(vbuf->planes[0]) * vb->num_planes);
--
2.25.0.341.g760bfbb309-goog
