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[2/2] s5p-mfc: use VB2_FILEIO_ALLOW_ZERO_BYTESUSED flag

Message ID 1418729778-14480-2-git-send-email-k.debski@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kamil Debski Dec. 16, 2014, 11:36 a.m. UTC 
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.debski@samsung.com>
---
 drivers/media/platform/s5p-mfc/s5p_mfc.c |   11 +++++++++++
 1 file changed, 11 insertions(+)
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Patch

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);