imx6q IPU 'flip irq' error

[user123412]

Hello,

I have been debugging an issue with an imx6q-based board (Yocto Dunfell, Linux 5.4, Uboot 2020.04) where periodically (1-10% of the time depending on the hardware) the LVDS display will not turn on and the following message is printed from mxc_ipuv3_fb.c:

mxc_sdc_fb fb@0: timeout when waiting for flip irq

I have run thousands of power cycles on multiple boards with both 1 and 2 GB of RAM and it seems to only happen on the 1 GB devices, so the issue seems to be possibly memory-related. I've also seen multiple forum posts regarding this error, but have not actually seen an explanation as to why this happens or a solution. If I could get such an explanation of the issue, or possible solutions that would be great.   

[Zhiming_Liu]

Hi @user123412 

You can refer this guide:

https://www.nxp.com.cn/docs/en/engineering-bulletin/EB821.pdf?_gl=1*g9zyjf*_ga*NzA4NjkwNjg0LjE3MDU2M....

Here is other case, the patchs mentioned in this case have already exists in kernel.

https://community.nxp.com/t5/i-MX-Processors/mxc-sdc-fb-fb-16-timeout-when-waiting-for-flip-irq/m-p/...

You can check if the LVDS clock behavior is similiar with this:

Best Regards

Zhiming