Best kernel version for Retropie and KMS

[ecto]

Hi,

I have for some time now the KMSDRM driver installed and it worked well with Kernel 5.10.31.

Last week I tried installing Exult 1.8 which ended up with bad screen tearing. So I tried experimenting with a newer kernel (5.10.103, installed by apt upgrade). This lead to a black screen. The Pi was still communicating over SSH, so I was able to downgrade again.

I have now tried several kernels, but so far I always had some problems:

• black screens at startup right before Emulationstation loads. There has always been a small screen "dropout" at this time, but with a non working kernel the screen just stays black.
• the screen flickers off and on at random. Sometimes staying black, sometimes coming back to life after a longer period.

Right now I'm using kernel 5.10.72, and for a time everything was great (like Exult tear-free with VC4_DEBUG=always_sync). But suddenly the screen blackouts are back.

I just found a similar topic here on the forum, so the problem isn't new. But it has been a while and maybe there is a solution now?

Is it a KMS audio driver and/or pulseaudio problem? Is it a wrong configuration? Can I still fallback to the non KMS audio driver (well, al least I cant; I tried though)?

[Darksavior]

@ecto The bullseye os might have newer kms driver updates. It's using the 5.15 kernel. Retropie is still using the older buster os. Unfortunately, retropie is not supported on bullseye right now.

I've moved on to bullseye and haven't had the black screen issue. I did have to modify some retropie installer scripts and install a missing dependency to get it to install. Retroarch emulators seem to run fine but I've had audio dropouts with Redream.

[ecto]

@Darksavior Yesterday, I just tried sudo rpi-update which installed the latest 5.15.X kernel. As I'm still on Buster, I'm not sure if that was just a bad or a really bad idea... ^_^;
At least the system still boots, and in the limited time I tested I had sound and no screen tearing. But there was still another "blackout" for a second at some point.
I have not tested any emulators, just some ports (Exult and Quake) and some wine games (Deus Ex and Silent Hill 3)

[ecto]

Ok, the 5.15.? Kernel didn't work well. I had some screen dropouts again.
I then tried 5.10.60, which still had the screen tearing issue in Exult. After that I installed 5.10.64, which eliminates the screen tearing. So one of the commits between those versions fixed that. I will test this kernel further in the coming days and report back.