KMS goes to black screen with recent kernel

saccublenda

Hello,
I've noticed that with kernel versions > 5.10.46 and the KMS driver ES works ok, but when I launch a game with any emulator it goes to black screen (the tv shows "NO SIGNAL"). The verbose output logs show nothing interesting.
The latest kernel with which KMS works is 5.10.46.
Does anyone know the reason for that?

Pi Model or other hardware: pi4 4gb
Power Supply used: USB3.0
RetroPie Version Used: 4.7.18
Built From: https://github.com/RetroPie/RetroPie-Setup/releases/download/4.7.1/retropie-buster-4.7.1-rpi4_400.img.gz
USB Devices connected: bluetooth dongle
Controller used: 8bitdo sfc30 (bluetooth)

Darksavior

@saccublenda I just updated my pi4 to the latest stable kernel(5.10.52) and having the same issue with the kms driver. The fkms driver is fine.

Blerkotron

I have the same issue, my Pi 4 shuts down and I have to hard reset.

From the investigations I did, I think it is something to do with the audio - ES boots normally, but as soon as I do anything which would trigger a sound (even the 'click' when moving between games in the ES interface), the Pi crashes out to a black screen. If I disable ES sounds I can navigate normally but I hit the issue as soon as I launch a game.

Setting dtparam=audio=off in config.txt makes everything work fine, but obviously with no audio. I usually have 'noaudio' set on dtoverlay but I tried some experiments with that setting to see if there was any combination of audio settings that work, but if there is I can't find them.

For the moment I've just reverted to fkms, which is a shame because kms was working perfectly for me for several months.

Glad to see someone else with the issue, I've been Googling around for a while now but couldn't find anything - thought it was just my setup.

saccublenda

@blerkotron Yes, I confirm that, ES is working fine for me because I have switched off navigation sounds. It is a combination of new kernel, KMS and audio.
I wonder if it is a RetroPie problem or a kernel problem.

busywait

@saccublenda Yes, I've seen this. I asked about it on the Raspberry Pi forum: https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=316721

A few utilities to collect debug information were suggested, but they need building from source, I don't know how to use them, and I'm busy, so [shrug]

I assume that the Raspberry Pi OS team will be debugging this over the next few months as they move towards a Bullseye based release, so I'm just waiting.

busywait

An almost related comment from a Raspberry Pi engineer over on the RPi forums:

If [screen tearing] bothers you, it may be worth waiting for the bullseye image which will kms by default, which is the real solution for tearing

\o/

saccublenda

@busywait Yeah, I guess that a RetroPie image based on bullseye will fix it.

Darksavior

I tried the unofficial manual upgrade to bullseye but the problem didn't go away. I'm sure there's much more to it, but I wanted to try.
https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=317888

busywait

@darksavior I ran that script on a clean 64-bit install too. It was a smooth process but still some problems

I was warned on the forum that there are still missing packages in the raspberry pi maintained bullseye repos (that's independent of the debian Bullseye release and repos)
Raspberry Pi haven't previously supported upgrades to new OS versions
The package python3-sdl2 that is needed by the RetroPi installer doesn't install because of unmet dependencies (at least last week when I tried)
No, the blank screen issue is not fixed (yet?)

However, it will be good that kms becomes the default. I wonder how long until the RetroPie install script will support it [the bullseye distro]? 🤔

saccublenda

@busywait said in KMS goes to black screen with recent kernel:

I wonder how long until the RetroPie install script will support it?

I think we have to wait for an official bullseye Raspberry Pi OS image (2-4 months from now), and then for a RetroPie image based on the former.

Darksavior

@busywait I only tried 32 bit and retroarch wouldn't compile due to missing sdl2 dependancies until I used this repo https://github.com/joolswills/RetroPie-Setup/tree/sdl_2.0.16

saccublenda

Just as an update, the official bullseye Raspberry Pi OS image was just released.

sirhenrythe5th

@devs: just to get an idea: as soon as bullseye will be the base of retropie: will we have to build a new image, or will buster be upgradable to bullseye?

mitu

@sirhenrythe5th said in KMS goes to black screen with recent kernel:

will we have to build a new image, or will buster be upgradable to bullseye?

New image, as always.

sirhenrythe5th

@mitu thanks for info, i will start the backup :D

mitu

@sirhenrythe5th I wouldn't be in such a hurry.