How to configure fbdev interface in IMX6DL?

Technical Support
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#1

Hello world,
I’m trying to interface LCD with Generic RGB display, I’m using Toradex LXDE Demo Image, when LCD got connected, it is not displaying well, so I’m trying to configure the settings using fbdev interface,
this is what my configuration
Got this from logs

mxc_sdc_fb fb@0: 640x480 h_sync,r,l: 64,16,80 v_sync,l,u: 4,3,13 pixclock=23750000 Hz

Here I want to change h_sync,r,l and pixclock so can anyone tell me how to set these things in uboot terminal?

Thanks
Nolan

#2

You can do it through Device Tree Display Output, Resolution and Timings (Linux)

#3

Hi @alex.tx ,
I’m using IMX6DL, so need to edit imx6dl-colibri-eval-v3.dts, but here I dont see any lcdif node here to configure LCD.

For now I’m editing colibri-imx6_parallel-rgb_overlay.dts
display-vga_overlay.dts
editing these things I’m able to fit display screen some what closer to LCD. but for now touch is not working, the cursor is not moving.

this being done, with the help of display-vga_overlays.dts, not because of colibri-imx6_parallel-rgb_overlay.dts, because when I dont use display-vga_overlays.dts it is not taking any affect on screen size, but when I modify and add display-vga_overlays.dts it is reflecting on LCD screen.

So here are my question
1.Even though screen got fitted(not accurately), why touch is not working, which was working fine with default overlays.
2. why vga overlay taking effect on LCD screen why not parallel-rgb_overlay?

#4

Hi @Nolan_Maverick ,

The LXDE Demo Image you mentioned is BSP 2.8, which does not support device tree overlays. Overlays were introduced starting from BSP 5. Can you please confirm the BSP version you are working with?

Could you please share your device tree here so that we can have a look?

Furthermore, a link to the display you’re using might be useful as well.

Have a great day!

Best Regards
Kevin

#5

Hi @kevin.tx,
Sorry for not mentioning, now I’m using Torizoncore, there I’m runnning container Image wayland-base
these are the overlays please look into it
colibri-imx6_parallel-rgb_overlay.dts (420 Bytes)
display-vga_overlay.dts (778 Bytes)’

Note that touch is working, it is not accurate, if I press in some location, reaction is happening in different location.

#6

Hi @kevin.tx,
with those dts fils itself my window got fitted, but now the problem is Yaxis is inverted,
So i gone through this link

and noted tried this

echo 'ENV{LIBINPUT_CALIBRATION_MATRIX}="1 0 0 0 -1 1"' > /etc/udev/rules.d/libinput.rules

but it throws error because udev folder itself is missing, So can you tell me what is the way to invert the touch reaction?

thanks
Nolan

#7

Hi @Nolan_Maverick ,

Since this topic seems to be solved we will close this ticket and answer your other question in the new thread that you created related to that.