MX8-DSI-OLED1A display latency more than 2s

[Laiweiyu]

Hi NXP

I have I.MX 8M Mini LPDDR4 EVK board & MX8-DSI-OLED1A panel & NXP MIPI CSI camera.

First, I download pre-build image(version=LF_v5.15.52-2.1.0_images_IMX8MMEVK),

and flash microSD by command

sudo dd if=imx-image-full-imx8mmevk.wic of=/dev/sdc bs=1M conv=fsync

In u-boot set:

setenv fdtfile imx8mm-ddr4-evk-rm67199-cmd-ram.dtb

run bootcmd

It can success display,and I run below Gstreamer test 

case 1. Camera CSI  -> DSI-OLED1A (display real time)

gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw, format=YUY2, width=1920, height=1080, framerate=30/1' ! autovideosink

case 2. TS file -> decode -> DSI-OLED1A(display real time)

gst-launch-1.0 filesrc location=test720p.ts ! tsparse ! tsdemux ! queue ! h264parse ! v4l2h264dec ! autovideosink

case 3. Camera CSI  -> H264 encode -> H264 decode -> DSI-OLED1A(display more than 2s latency)

gst-launch-1.0 v4l2src ! 'video/x-raw, format=YUY2, width=1280, height=720, framerate=30/1' ! v4l2h264enc ! queue ! h264parse ! mpegtsmux ! tsparse ! tsdemux ! queue ! h264parse ! v4l2h264dec ! autovideosink sync=false

case 4. Ethrrnet -> H264 decode -> DSI-OLED1A(display more than 2s latency)

gst-launch-1.0 udpsrc port=1234 ! application/x-rtp,media=video,clock-rate=90000,encode-name=MP2T-ES,payload=33 ! rtpmp2tdepay ! tsparse ! tsdemux ! queue ! h264parse ! v4l2h264dec ! autovideosink sync=false

But,case 3 and case 4 if I use HDMI out( boot set default dtb file ,MIPI DSI convert to HDMI out) ,

HDMI out can display real time when run same gstreamer cammand.

I want to know the reason and how can I improve it ? 

thanks

[Zhiming_Liu]

Hi @Laiweiyu ,

Have you compared the imx8mm-ddr4-evk-rm67199.dtb?

Best Regards

Zhiming

[Laiweiyu]

Hi Zhiming

Thanks reply

I already tried "imx8mm-ddr4-evk-rm67199.dtb",but it can't display

This issue makes me very troubled...

[Zhiming_Liu]

The RM67199 support two operation modes: command mode and video mode.

Command Mode refers to operation in which transactions primarily take the form of sending commands and data to a display module that incorporates a display controller. The display controller may include local registers and a frame buffer[in RM67199]. Systems using Command Mode write to, and read from, the registers and frame buffer memory. The host processor indirectly controls activity at the peripheral by sending commands, parameters and data to the display controller.

Video Mode refers to operation in which transfers from the host processor to the peripheral take the form of a real-time pixel stream.

The imx8mm-evk-rm67199-cmd-ram.dts will make rm67199 work at Command Mode, the command mode will cost time to display the correct pixel.

So you should use imx8mm-evk-rm67199.dts, can you share the kernel log when you use this dtb?

[Laiweiyu]

Log in attach file

setenv fdtfile imx8mm-evk-rm67199.dtb

The panel shows shortly "LINUX penguin" ,and then can't display anymore

if necessary,I can use camera record

Thanks

[Zhiming_Liu]

Hi @Laiweiyu 

At the moment i only  have i.mx8mpevk and OLED1.The attachment is my test log with imx8mp-evk-rm67199.dtb. Do you have other i.MX platform or OLED panel? You can test if this panel is broken.

I have I.MX 8M Mini LPDDR4 EVK board 

-->But you use ddr4 dtb, you should use imx8mm-evk-rm67199.dtb

L5.15.52 with ubuntu

L5.15.32

[Laiweiyu]

I already use " imx8mm-evk-rm67199.dtb" , but it can't display,

And I only have I.MX 8M Mini LPDDR4 EVK board & MX8-DSI-OLED1A panel

I take some pictures show this issue 

[Zhiming_Liu]

Hi @Laiweiyu 

Checked the panel part number in my side, it's same as yours(SCH-29834_A).

You need saveenv after you setenv.

[Laiweiyu]

I tried,but this dtb still can't display,

maybe the reason is that yours panel is MX8-DSI-OLED1,my panel is MX8-DSI-OLED1A ?

[Zhiming_Liu]

We are using same panel:

You can contact NXP to return this panel as it maybe a quality issue.

[Laiweiyu]

OK, I return this panel and get new panel,

and I use newest version image(L5.15.71_2.2.0_MX8MM).

It can display when set "imx8mm-evk-rm67199.dtb"

Thanks