FAILED: patch "[PATCH] media: nxp: imx8-isi: Reduce minimum queued buffers from 2 to" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] media: nxp: imx8-isi: Reduce minimum queued buffers from 2 to" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 2f38622d0f85f317be9e6b131da6cd511db94fd2
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026051506-heave-police-4137@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2f38622d0f85f317be9e6b131da6cd511db94fd2 Mon Sep 17 00:00:00 2001
From: Guoniu Zhou <guoniu.zhou@nxp.com>
Date: Thu, 12 Mar 2026 11:12:34 +0800
Subject: [PATCH] media: nxp: imx8-isi: Reduce minimum queued buffers from 2 to
 0

Fix a hang issue when capturing a single frame with applications like cam
in libcamera. It would hang waiting for the driver to complete the buffer,
but streaming never starts because min_queued_buffers was set to 2.

The ISI module uses a ping-pong buffer mechanism that requires two buffers
to be programmed at all times. However, when fewer than 2 user buffers are
available, the driver use internal discard buffers to fill the remaining
slot(s). Reduce minimum queued buffers from 2 to 0 allows streaming to
start without any queued buffers.

Fixes: cf21f328fcaf ("media: nxp: Add i.MX8 ISI driver")
Cc: stable@vger.kernel.org
Signed-off-by: Guoniu Zhou <guoniu.zhou@nxp.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patch.msgid.link/20260312-isi_min_buffers-v2-1-d5ea1c79ad81@nxp.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

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 13682bf6e9f8..1be3a728f32f 100644
--- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c
+++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-video.c
@@ -1410,7 +1410,7 @@ int mxc_isi_video_register(struct mxc_isi_pipe *pipe,
 	q->mem_ops = &vb2_dma_contig_memops;
 	q->buf_struct_size = sizeof(struct mxc_isi_buffer);
 	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
-	q->min_queued_buffers = 2;
+	q->min_queued_buffers = 0;
 	q->lock = &video->lock;
 	q->dev = pipe->isi->dev;