07-31-2017 04:28 PM
The DisplayPort Subsystem has live vide input and output ports from the PL for enabling live video overlays/previews. I have successfully got the HSYNC and VSYNC to toggle (on the live video output) but I can't get a framebuffer to output any pixel data to the live video pixel output. I am not using the DisplayPort Source Controller. Here is the path that we want to use:
The PL has a parallel TFT LCD connected. We have verified with an ILA in the PL that only HSYNC/VSYNC toggle.
Any advice? Has anyone successfully gotten the Blended Video to PL to work?
12-13-2017 04:17 AM
Sorry you had no response when you have written this post. I missed this thread.
Do you have any updates on this?
In case you still have issues:
Are you trying to use both the live input and output? Do you have any output on the DP controller?
12-13-2017 08:42 AM
Thanks for the followup. We were NOT using DisplayPort on the GTR(s). We got this to work by commenting some lines out of the DP/DRM drivers and loading them anyway. It's still not clear how much of the DP/DRM subsystem driver(s) are required to enable the functionality - but we did get something to work. It would be great if those driver(s) had a device tree flag for "live-vid-only" or something.
In our use case, we were only trying to use the live video output from a linux framebuffer - but I could see where taking live video input and having alpha blending, etc - would be a useful and valid use case.
12-13-2017 08:53 AM
Yes as far as I know, the current Xilinx driver does not support live output only so modifying the driver is probably the right way to go. It might be implemented later