OV5647 camera probe failing with error -121 on Raspberry Pi

Raspberry Pi Cameras
1

Hey everyone, I’m trying to get an OV5647 camera module working on my Raspberry Pi but it’s just not being detected at all. I’ve already enabled the camera interface through raspi-config and rebooted, but no luck. Anyone have ideas on what else I should check?

2

Welcome! Let’s start with some basics. Could you run rpicame-hello in the terminal and post the output? That’ll tell us if the system sees any camera at all. Also, what does dmesg show for camera-related entries? You can check with: dmesg | grep -i ov5647

3

Thanks for the quick reply. Here’s what I’m getting:

rpicame-hello just says:

No cameras available!

And dmesg shows this:

[2.050593] rp1-cfe 1f00128000.csi: found subdevice /axi/pcie@1000120000/rp1/i2c@80000/ov5647@36
[2.319681] ov5647 11-0036: probe with driver ov5647 failed with error -121

So it looks like something is partially detected but then fails. Not sure what error -121 means though.

4

Good find — that dmesg output is really telling. Error -121 is EREMOTEIO, which means the I2C communication between the Pi and the camera sensor is failing. The interesting part is that the CSI subdevice is being found at i2c address 0x36, so the system knows something is on the bus, but when the ov5647 driver tries to actually talk to the sensor, it gets nothing back.

This almost always points to a physical connection issue rather than a software problem. The most common culprits are:

  • Ribbon cable not seated properly (even slightly crooked can cause this)
  • Cable inserted the wrong way around on one or both ends
  • A damaged ribbon cable (they’re fragile)

Before we go deeper into software debugging, let’s rule out the physical layer first. Could you provide:

  1. Clear, well-lit photos showing both ends of the ribbon cable — where it connects to the camera module and where it connects to the Raspberry Pi. Make sure the contacts are visible.

  2. Also, let’s gather a full diagnostic snapshot. Run these commands in order:

sudo reboot
wget -O arducam-camera-bug-report https://github.com/Dion4cen/arducam-camera-bug-report/releases/download/Tool/arducam-camera-bug-report
chmod +x ./arducam-camera-bug-report
./arducam-camera-bug-report

Once that finishes, you’ll have a file called arducam-bug-report.txt in the current directory. Attach that along with the photos and we’ll go from there.

5

Okay, I’ll grab those photos and run the diagnostic. Give me a few minutes — I need to power everything down and reseat the cable anyway just to see if that helps. Will post back soon with the pics and the bug report file.

6

Sounds good, take your time. While you’re at it, when you reseat the ribbon cable, pay extra attention to the orientation — the blue tab side on the Pi’s camera connector should face the Ethernet port, and on the camera board side the contacts should line up properly (silver contacts facing the right direction). A lot of these -121 errors end up being a flipped cable on one end. We’ll take a look at everything once you post back.