Hi Frank,

Thanks for your review.

-----Original Message-----
From: Frank Li <frank.li@nxp.com>
Sent: Wednesday, March 11, 2026 11:34 PM
To: G.N. Zhou (OSS) <redacted>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>; Mauro Carvalho
Chehab [off-list ref]; Sascha Hauer [off-list ref];
Pengutronix Kernel Team [off-list ref]; Fabio Estevam
[off-list ref]; linux-media@vger.kernel.org; imx@lists.linux.dev;
linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; Alexi
Birlinger [off-list ref]; G.N. Zhou [off-list ref]
Subject: Re: [PATCH 2/2] media: nxp: imx8-isi: Prioritize pending buffers over
discard buffers

On Wed, Mar 11, 2026 at 04:02:59PM +0800, Guoniu Zhou wrote:

quoted

From: Guoniu Zhou <redacted>

Change the buffer selection logic to use pending buffers first (up to
the number available), and only use discard buffers to fill remaining
slots when insufficient pending buffers are queued. This ensures user
buffers

Nit: Ensure user ...

Will update.

quoted

are utilized as soon as possible, improving efficiency and reducing
the number of discarded frames at stream start.

For example:
- 2 pending buffers: both slots use pending buffers
- 1 pending buffer: first slot uses pending, second uses discard
- 0 pending buffers: both slots use discard buffers

Signed-off-by: Guoniu Zhou <redacted>
---
 drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c

b/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c
index

2405baf21594cd18cf2b349234313c5e103b7802..53f4f74369f7855fe6b6f372
294e

quoted

e569f40a8ae6 100644

--- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c
+++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c

@@ -786,13 +786,14 @@ static void

mxc_isi_video_queue_first_buffers(struct mxc_isi_video *video)

quoted

 		: list_is_singular(&video->out_pending) ? 1
 		: 0;

+	/* Queue buffers: prioritize pending buffers, then discard buffers
+*/
 	for (i = 0; i < 2; ++i) {
 		enum mxc_isi_buf_id buf_id = i == 0 ? MXC_ISI_BUF1
 					   : MXC_ISI_BUF2;
 		struct mxc_isi_buffer *buf;
 		struct list_head *list;

-		list = i < discard ? &video->out_discard : &video->out_pending;
+		list = (i < 2 - discard) ? &video->out_pending :
+&video->out_discard;

Is (2 - discard) the number of pending buffers? put commit's example as
comments here.

Yes, will update in next version.

Frank

quoted

 		buf = list_first_entry(list, struct mxc_isi_buffer, list);

 		mxc_isi_channel_set_outbuf(video->pipe, buf->dma_addrs,

buf_id);

quoted

--
2.34.1