VLC not working with full KMS on Pi 4?

[Setiawan]

I've posted this in the Raspberry Pi forums, but haven't got much luck. Hoping I have more luck here.

I've described my current set up more or less in this post on the Raspberry Pi forums. To summarise though, I've installed Raspberry Pi OS Lite (no GUI) on my Pi 4, updated to the latest kernel, and am using a custom driver/module that allows for interlaced video over DPI. This custom driver requires the use of the vc4-kms-v3d overlay, as well as its own vc4-vga666 overlay. My VLC version is 3.0.12.

Problem: When I try to play a video with VLC, the audio plays but no video is displayed. If I switch back to fake KMS and the regular vga666 overlay, the video plays. I can also get the video to play if I use an X display, but I would rather not as it doesn't seem to handle interlaced resolutions well.

Can anyone confirm whether VLC should be working with full KMS on Pi 4?

I've uploaded the verbose log that I get when running VLC with the -vv arg to this pastebin, in case anyone can see what's wrong.

[Rémi Denis-Courmont]

No. VLC support for KMS is extremely limited at this time.

[Setiawan]

That's a shame, but thank you for letting me know. Do you know if it's something that's actively being worked on, or what developments I should look out for?

[Rémi Denis-Courmont]

I don't know what other people may be doing.