Troubleshooting • Using MIPI DSI LCD on cm4

Hi,

STATUS :
I'm using cm4, and Raspberry PiOS with desktop
Release date: March 15th 2024
System: 64-bit
Kernel version: 6.6
Debian version: 12 (bookworm)

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I treid :
1. The LCD (connected to DISP1) I bought from waveshare works fine. But I have to use a commercial LCD.
HDMI works well.

2. Trying to use MIPI DSI LCD(AUO B101EAN01.5 1280x800 resolution, it has four-lane) (connected to DISP1)

The latest bookworm includes dtoverlay : vc4-kms-dsi-generic.
So I modified /boot/firmware/config.txt as follows.

dtoverlay=vc4-kms-v3d
dtoverlay=vc4-kms-dsi-generic,four-lane,
dsi1=<&dsi_frang>,target=<&dsi1>
dtparam=clock-frequency=6666667
dtparam=hactive=1280,hfp=18,hsync=32,hbp=21
dtparam=vactive=800,vfp=4,vsync=18,vbp=8
dtparam=width-mm=220,height-mm=70
or
lcd_ignore=1
dtoverlay=vc4-kms-v3d
dtoverlay=vc4-kms-dsi-generic,hactive=1280,vactive=800,dsi1=<&dsi_frang>,target=<&dsi1>,four-lane
or
dtoverlay=vc4-kms-v3d
dtoverlay=vc4-kms-dsi-generic,hactive=1280,vactive=800,dsi1=<&dsi_frang>,target=<&dsi1>,four-lane
many things.

3. I type 'kmsprint' or 'xrandr' in the command window
It says dsi-1 connected.
Also I verified that HDMI-1 and DSI-1 both were connected in the Raspberry Screen Configuration.

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NOW :
But MIPI LCD is still black screen. HDMI works well.

Can you tell me what I'm doing wrong?
I'm asking for your help.


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For your information,
My colleague turned on the same LCD in the following way.
However, I don't think it's the right way to get a kernel from a lower version and compile it and use it.
I think it should be available in the latest version as well.

OTHER WAY :
System: 64-bit
Kernel version: 6.1
Debian version: 11 (bullseye)

git clone --depth=1 --branch rpi-6.1.y https://github.com/raspberrypi/linux
cd linux
KERNEL=kernel8
make bcm2711_defconfig
make menuconfig
make -j4 Image modules dtbs
sudo make modules_install
sudo cp arch/arm64/boot/dts/broadcom/*.dtb /boot/
sudo cp arch/arm64/boot/dts/overlays/*.dtb* /boot/overlays/
sudo cp arch/arm64/boot/dts/overlays/README /boot/overlays/
sudo cp arch/arm64/boot/Image /boot/kernel8.img

Modify /boot/config.txt as follows

lcd_ignore=1
dtoverlay=vc4-kms-v3d
dtoverlay=vc4-kms-dsi-generic,hactive=1280,vactive=800,dsi1=<&dsi_frang>,target=<&dsi1>,four-lane

Statistics: Posted by Sonia_83 — Wed May 22, 2024 1:37 am

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