On Thu, Feb 19, 2026 at 05:19:46PM +0100, Michael Riesch wrote:

On 2/19/26 10:13, Laurent Pinchart wrote:

quoted

On Mon, Feb 16, 2026 at 02:49:57PM +0100, Michael Riesch via B4 Relay wrote:

quoted

From: Michael Riesch <michael.riesch@collabora.com>

Each stream requires CIF_REQ_BUFS_MIN=1 buffers to enable streaming.
However, it failed with only one buffer provided.

Comply with the minimum number of buffers requirement and accept
exactly one buffer.

Fixes: 501802e2ad51 ("media: rockchip: rkcif: add abstraction for dma blocks")
Cc: stable@kernel.org
Signed-off-by: Michael Riesch <michael.riesch@collabora.com>
---
 .../media/platform/rockchip/rkcif/rkcif-stream.c   | 41 +++++++++++-----------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/drivers/media/platform/rockchip/rkcif/rkcif-stream.c b/drivers/media/platform/rockchip/rkcif/rkcif-stream.c
index e00010a91e8b..5a5ab9e7e86e 100644
--- a/drivers/media/platform/rockchip/rkcif/rkcif-stream.c
+++ b/drivers/media/platform/rockchip/rkcif/rkcif-stream.c

@@ -106,19 +106,6 @@ static int rkcif_stream_init_buffers(struct rkcif_stream *stream)
 {
 	struct v4l2_pix_format_mplane *pix = &stream->pix;
 
-	stream->buffers[0] = rkcif_stream_pop_buffer(stream);
-	if (!stream->buffers[0])
-		goto err_buff_0;
-
-	stream->buffers[1] = rkcif_stream_pop_buffer(stream);
-	if (!stream->buffers[1])
-		goto err_buff_1;
-
-	if (stream->queue_buffer) {
-		stream->queue_buffer(stream, 0);
-		stream->queue_buffer(stream, 1);
-	}
-
 	stream->dummy.size = pix->num_planes * pix->plane_fmt[0].sizeimage;
 	stream->dummy.vaddr =
 		dma_alloc_attrs(stream->rkcif->dev, stream->dummy.size,

@@ -132,16 +119,30 @@ static int rkcif_stream_init_buffers(struct rkcif_stream *stream)
 			stream->dummy.buffer.buff_addr[i - 1] +
 			pix->plane_fmt[i - 1].bytesperline * pix->height;
 
-	return 0;
+	stream->buffers[0] = rkcif_stream_pop_buffer(stream);
+	if (!stream->buffers[0])
+		goto err_buff_0;

Why do you move this after allocation of the dummy buffer, to then add
dma_free_attrs() in the err_buff_0 error path ?

To keep the two rkcif_stream_pop_buffer calls together. We need to
allocate the dummy in any case, but in case the second pop fails we use
it -- this was not the case before.

I suppose it's easier than returning buffers[0] in the dummy buffer
allocate error path. Works for me.

quoted

quoted

-err_dummy:
-	rkcif_stream_return_buffer(stream->buffers[1], VB2_BUF_STATE_QUEUED);
-	stream->buffers[1] = NULL;
+	stream->buffers[1] = rkcif_stream_pop_buffer(stream);
+	if (!stream->buffers[1]) {
+		stream->buffers[stream->frame_phase] = &stream->dummy.buffer;
+		stream->buffers[stream->frame_phase]->is_dummy = true;
+	}
+
+	if (stream->queue_buffer) {
+		stream->queue_buffer(stream, 0);
+		stream->queue_buffer(stream, 1);
+	}
+
+	return 0;
 
-err_buff_1:
-	rkcif_stream_return_buffer(stream->buffers[0], VB2_BUF_STATE_QUEUED);
-	stream->buffers[0] = NULL;
 err_buff_0:
+	dma_free_attrs(stream->rkcif->dev, stream->dummy.size,
+		       stream->dummy.vaddr,
+		       stream->dummy.buffer.buff_addr[0],
+		       DMA_ATTR_NO_KERNEL_MAPPING);
+	stream->dummy.vaddr = NULL;
+err_dummy:
 	return -EINVAL;

You can drop the err_dummy label and return -EINVAL directly. Except you
should probably return -ENOMEM as the failure comes from
dma_alloc_attrs().

Makes sense, will fix.

quoted

quoted

 }
 

-- 
Regards,

Laurent Pinchart