i.MX ProcessorsのトピックSubject: Application crashes after "mxc_v4l_dqueue timeout enc_counter 0" on i.MX6 (kernel 4.9.88)

Subject: Application crashes after "mxc_v4l_dqueue timeout enc_counter 0" on i.MX6 (kernel 4.9.88)

hasisb — Mon, 26 May 2025 12:33:00 GMT

Hi,

I'm working on an NXP i.MX6-based system running Linux kernel 4.9.88. I'm using a custom camera application that interfaces with V4L2 and the IPU (CSI/IC).

After running for some time, the application crashes, and I see the following messages in the kernel log:

[ 265.260910] imx-ipuv3 2400000.ipu: IPU Warning - IPU_INT_STAT_5 = 0x00800000

[ 265.260923] imx-ipuv3 2400000.ipu: IPU Warning - IPU_INT_STAT_10 = 0x00080000 [12461.922418] ERROR: v4l2 capture: mxc_v4l_dqueue timeout enc_counter 0

[12610.379560] send_sig_info error
[12610.396334] send_sig_info error
[12610.413113] send_sig_info error
[12610.429887] send_sig_info error
..

Shortly after this, the application exits with code 255 (checked with "echo $?"). Also, in some cases, the message send_sig_info error appears in dmesg.

From what I can tell:

The camera pipeline works for a while (changed between 2 and 7.5 hours) and then stops.
The mxc_v4l_dqueue() function appears to timeout, likely due to no frames being dequeued from the IPU buffer.
This eventually leads to the application terminating.

My questions:

What exactly does enc_counter 0 indicate in this context?
What could cause the mxc_v4l_dqueue() timeout — sensor failure, IPU issue, or buffer mismanagement?
Are there known stability issues in the IPU or V4L2 stack in kernel 4.9.88?
Is there any recommended workaround or patch for this issue?

Any guidance or suggestions would be greatly appreciated.

Thanks,

Re: Subject: Application crashes after "mxc_v4l_dqueue timeout enc_counter 0" on i.MX6 (ke

Bio_TICFSL — Mon, 26 May 2025 14:49:15 GMT

Hello,

A1.

IPU_INT_STAT_10 means AXI read access error, one can check programming requirements provided for AXIR units in sect.37.4.2.4.1 Handling real time channels,

37.4.2.5, Table 37-15 i.MX6DQ Reference Manual

http://www.nxp.com/docs/en/reference-manual/IMX6DQRM.pdf

A2. The que wait to much for buffer fullfil check your camera and check the dtb

A3. No

A4.

You need to add the following line when defining your capture device:

VideoCapture cap("imxv4l2videosrc device=\"/dev/video0\" ! videoconvert ! appsink")

This worked with the Analogue Camera Adapter. For you webcam, you may need different videosources. The different video sources can be found with the command gst-inspect-1.0 | grep v4l2 on the EVK.

Regards

Re: Subject: Application crashes after "mxc_v4l_dqueue timeout enc_counter 0" on i.MX6 (ke

hasisb — Tue, 27 May 2025 09:17:56 GMT

A have already checked camera and DTB (since everthing works fine for hours i assume DTB is valid). BT1120 video comes through FPGA (cyclone5). imx6 board record and saves it into ssd using Gstreamer framework. What could be the problem?

Actually my system worked fine until last week.

Also i have disabled (by adding a register into FPGA) video and no error is encountered. just video stopped recording.

Re: Subject: Application crashes after "mxc_v4l_dqueue timeout enc_counter 0" on i.MX6 (ke

hasisb — Thu, 29 May 2025 05:49:23 GMT

I have also found following issue. very similar to my case

https://community.nxp.com/t5/i-MX-Processors/ERROR-v4l2-capture-mxc-v4l-dqueue-interrupt-received/td-p/575901

Is it a problem playback and video capture at the same time. Actually i dont playback video but Terminal screen keep playback all the time. If it a problem because in some cases it throws ERROR: v4l2 capture: mxc_v4l_dqueue() interrutpt recieved.
1. How to disable it?