i.MX ProcessorsのトピックiMX8M Plus 2nd MIPI CSI Camera : FIFO Overflow Error

iMX8M Plus 2nd MIPI CSI Camera : FIFO Overflow Error

baek — Thu, 01 Jul 2021 10:08:24 GMT

Hi,

I am developing a dual camera application.

Camera resolution and image format is 2592x1944, RAW8

Datapath and driver structure is

Camera (sensor driver.c)--> MIPI-CSI2 (imx8-mipi-csi2-sam.c) --> ISI (imx8-isi-cap.c) --> RAM

After modifying the drivers, I could get the video stream from CSI1 successfully with 2592x1944, RAW8, 50~60fps.

Now I want to get another video stream from CSI2, but not working because of FIFO overflow error.

[ 43.892406] mxc-mipi-csi2.1: Frame End events: 1
[ 43.897023] mxc-mipi-csi2.1: Frame Start events: 2
[ 43.901811] mxc-mipi-csi2.1: Non-image data after odd frame events: 0
[ 43.908248] mxc-mipi-csi2.1: Non-image data before odd frame events: 0
[ 43.914771] mxc-mipi-csi2.1: Non-image data after even frame events: 0
[ 43.921297] mxc-mipi-csi2.1: Non-image data before even frame events: 0
[ 43.927906] mxc-mipi-csi2.1: Unknown Error events: 0
[ 43.932868] mxc-mipi-csi2.1: CRC Error events: 0
[ 43.937484] mxc-mipi-csi2.1: ECC Error events: 0
[ 43.942097] mxc-mipi-csi2.1: FIFO Overflow Error events: 1209788
[ 43.948100] mxc-mipi-csi2.1: Lost Frame End Error events: 0
[ 43.953672] mxc-mipi-csi2.1: Lost Frame Start Error events: 0
[ 43.959413] mxc-mipi-csi2.1: SOT Error events: 0

I tried to change hs-settle and clk-settle parameters, but no success.

Based on Reference Manual, CSI1 maximum operating frequency is 500MHz, but CSI2 is 266MHz.

Does the lower CSI2 frequency limit frame resolution or frame rate?

How can I solve this ?

Re: iMX8M Plus 2nd MIPI CSI Camera : FIFO Overflow Error

igorpadykov — Thu, 01 Jul 2021 23:26:02 GMT

Hi Dy

yes you are right, fifo overflow may be caused by isi performance capabilities, as

described in sect.13.1.2 Display Interface i.MX 8M Plus Applications Processor Reference Manual

"The key features of the ISI include:..
Image processing for
• 2 processed camera stream at 1080p30
• 2 unprocessed camera stream (i.e. no scaling) at 4Kp30, depending on
system load and use case..
When two ISPs are used simultaneously, each supports:
• maximum resolution up to 1080p (1936x1188)"

Best regards
igor

Re: iMX8M Plus 2nd MIPI CSI Camera : FIFO Overflow Error

baek — Fri, 02 Jul 2021 01:01:45 GMT

Hi, igorpardykov

Thank you for your support.

I checked below from Reference Manual again.

• 2 unprocessed camera stream (i.e. no scaling) at 4Kp30, depending on
system load and use case

I want to get RAW8 format video stream (bypass csc), and then it corresponds unprocessed stream, am I right?

Does this mean that ISI supports using two 4Kp30 video streams simultaneously?

If I slow down 2nd frame rate (e.g under 30fps), can I solve FIFO overflow issue?

When two ISPs are used simultaneously, each supports:
• maximum resolution up to 1080p (1936x1188)"

FYI, I don't use ISPs at all (all disabled at the device tree), and use ISI only.

Thank you in advance.