trying to use KMS driver yields no composite video output (Raspberry Pi 4)

[Mrakobijes]

Hello everyone,
since I am experiencing a lot of screen tearing in games, I wanted to switch from the fake KMS to the full KMS driver. However, trying to do so either causes the Pi to boot without video output (the music in EmulationStation still plays normally), or it gives me the following error:

lvl0: Error creating SDL window!
Could not get EGL display
lvl0: Renderer failed to initialize!
lvl0: Window failed to initialize!

The lack of output occurs when I use the line:
dtoverlay=vc4-kms-v3d

The latter problem occurs if i use any of the following lines in config.txt:
dtoverlay-vc4-kms-v3d,composite=1
dtoverlay-vc4-kms-v3d-pi4,composite=1
dtoverlay= vc4-kms-v3d

Here is my full config.txt as of now:

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=0

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
overscan_left=16
overscan_right=16
overscan_top=16
overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=2
##hdmi_mode=4

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
arm_freq=2147
over_voltage=8
gpu_freq=750

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
#dtoverlay=vc4-fkms-v3d
dtoverlay-vc4-kms-v3d,composite=1
enable_tvout=1
max_framebuffers=2
#hdmi_ignore_edid=0xa5000080
#arm_64bit=1
gpu_mem=320 

[all]
#dtoverlay=vc4-fkms-v3d
force_turbo=1
#2 line For CPU Overclock
#over_voltage=
#arm_freq=
#2 line For GPU Overclock
#gpu_freq=
gpu_freq_min=500
#over_voltage=
audio_pwm_mode=0

Is there anything I can do to make the KMS driver work? Thanks in advance.

[mitu]

@Mrakobijes said in trying to use KMS driver yields no composite video output (Raspberry Pi 4):

dtoverlay-vc4-kms-v3d-pi4,composite=1

This looks like a mis-spelling, it should be just:

dtoverlay=vc4-kms-v3d,composite=1

and you should start with stock config.txt, instead of the one you're using, which has too many overclocking options which may conflict.

Note that this configuration is not fully supported by RetroPie yet and for the KMS driver is recommended to use an up-to-date Linux kernel/firmware.

You