Data not available on LVDS display when use LCDIF source

[nirmalluhana]

Hello folks,

Release: Yocto-Sumo (4.14.78_1.0.0_GA)

Board: i.MX8MQ based custom board

We are working on iMX8MQ based custom-designed board and we are facing issues in LVDS display when using LCDIF source for display. We only get the clock signals on clock lines and it is verified on MDO.

We tried with the DCSS source for display and it works perfectly with our LVDS display.

We also find a similar kind of issue on the NXP community on the below link but unfortunately, there is no solution available.

Link: https://community.nxp.com/thread/489422 

Does anyone provide the solution for this issue? Any guidance or suggestions will be really helpful.

Best regards,

Nirmal

[tuongnguyenmanh]

Hi  NIRMAL LUHANA,

Have you gone through this link: How to use dual display on i.MX8 including 4k decoding - i.MXDev Blog.

It shows dual display HDMI 4k@60 and MIPI-DSI 720p@60.

Have you tried LCDIF with lower resolution, ex. 720p?

[igorpadykov]

Hi Nirmal

issue may be related to clock limitations, one can check int valid_clocks[]
nwl-dsi.c\bridge\drm\gpu\drivers - linux-imx - i.MX Linux kernel 
One can try patches like :
MLK-21958-6: drm/bridge: nwl: Improve the clock calculation · kopera/linux-imx@80eb057 · GitHub 

Best regards
igor
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[johncoll]

Hi igorpadykov!

I've already applied the patch to kernel 4.14.98_2.0.0_GA, the LCD worked with DCSS but still can not work with LCDIF controller. Our board used SN65DSI83 as MIPI-LVDS converter.

Any advice?

[liyu1]

Hi:

      igorpadykov !

        I have the same problem. My application environment is as follows。

        OS ：android 9  2.3.0 or 1.0.0

        hardware : i.mx8mq 

        I use HDMI to drive ch7107b （HDMI - > CVSB）, and Mipi DSI interface to drive Mipi panel (ICN6211 MIPI DSI ->RGB24)。

        I can drive Mipi screen through DCSS ，But HDMI and Mipi display cannot be displayed at the same time.

        My question is:

         1. How to set HDMI resolution size ？

         2. How to make HDMI (720x 576 or 720x480 to cvbs) and Mipi panel (800 x480) work at the same time ?