PROCESSOR-SDK-J721E: Display port not working in SDK 10.01

Hi Rejin,

Could you try applying this patch: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=ti-linux-6.6.y&id=118cf0c8b392bed94437f1519de10b63705dbacd

There was a known issue on 9.2/10.0 timeframe with display, fixed by above commit.

In case the above patch does not work, I see in shared logs that connector probe was deferred. Is this using TI J721E EVM board and the default SDK image with no change to dts or kernel?

Regards,

Takuma

Hi Takuma,

I am using TI J721E EVM board and I used the prebuild image exist in the SDK for the creation of SD card.

After inspecting the file I found that the changes already exist in the file. I thing we need to rebuild linux OS. Please provide the procedure to rebuild the changes into SD card.

Regards,

Rejin

Hi Rejin,

I will recommend following the instructions here: https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-jacinto7/10_01_00_04/exports/docs/linux/Overview_Top_Level_Makefile.html#usage-examples 

The "Usage Examples" section is a good section to follow for building and installing Linux kernel.

Regards,

Takuma

Hi Takuma,

I followed the steps mentioned in the link. But in that link they are saying that we need to build kernel module because some modules will not be build with the above steps.

How we build the module.

Regards,

Rejin

Hi Rejin,

For display changes, the changes are all not out of tree, so using the "Top Level Makefile" is sufficient. However, if you want to build out of tree kernels like the GPU driver (which is not necessary for display, but does accelerate graphics), then there are two options:

• Yocto build: https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-jacinto7/10_01_00_04/exports/docs/linux/Overview_Building_the_SDK.html
• A standalone build of GPU driver: https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-jacinto7/10_01_00_04/exports/docs/linux/Foundational_Components/Graphics/Rogue/Build_Guide.html

Yocto build takes much longer to run initial build (potentially half a day on a good PC), but once it is built it will have everything for Linux, including kernel image, filesystem, and out of tree modules. Additionally, the second build and onward will used cached data, so it will not take as long.

Standalone build only builds GPU driver, so it takes less time. However, it only builds GPU driver, so if you eventually move to Yocto to modify what to include in filesystem, then the set up for this may be redundant.

In any case, for debugging purposes for the dark screen, my recommendation is to simply use the "Top Level Makefile" to modify the kernel/kernel modules with the commit.

Regards,

Takuma