The MFC driver interprets a buffer with bytesused equal to 0 as a special
case indicating end-of-stream. After vb2: fix bytesused == 0 handling
(8a75ffb) patch videobuf2 modified the value of bytesused if it was 0.
The VB2_FILEIO_ALLOW_ZERO_BYTESUSED flag was added to videobuf2 to keep
backward compatibility.
Signed-off-by: Kamil Debski <k.deb...@samsung.com>
---
drivers/media/platform/s5p-mfc/s5p_mfc.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc.c
b/drivers/media/platform/s5p-mfc/s5p_mfc.c
index 03204fd..89c148b 100644
--- a/drivers/media/platform/s5p-mfc/s5p_mfc.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc.c
@@ -820,6 +820,13 @@ static int s5p_mfc_open(struct file *file)
ret = -ENOENT;
goto err_queue_init;
}
+ /* One of means to indicate end-of-stream for MFC is to set the
+ * bytesused == 0. However by default videobuf2 handles videobuf
+ * equal to 0 as a special case and changes its value to the size
+ * of the buffer. Set the VB2_FILEIO_ALLOW_ZERO_BYTESUSED flag so
+ * that videobuf2 will keep the value of bytesused intact.
+ */
+ q->io_flags = VB2_FILEIO_ALLOW_ZERO_BYTESUSED;
q->mem_ops = &vb2_dma_contig_memops;
q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
ret = vb2_queue_init(q);
@@ -842,6 +849,10 @@ static int s5p_mfc_open(struct file *file)
ret = -ENOENT;
goto err_queue_init;
}
+ /* Set the VB2_FILEIO_ALLOW_ZERO_BYTESUSED flag, for more information
+ * please see the comment above.
+ */
+ q->io_flags = VB2_FILEIO_ALLOW_ZERO_BYTESUSED;
q->mem_ops = &vb2_dma_contig_memops;
q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
ret = vb2_queue_init(q);
--
1.7.9.5
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