KMS broken on rpi4 with linux-aarch64?

[greyltc]

Hi. The HDMI display connected to my raspberry pi 4, 8GB goes blank part way through the boot unless I use nomodeset in my kernel boot parameters
I'm using linux-aarch64
Anyone know how to get kms working?
Do I have to put something special in /boot/config.txt?

I've tried a few different displays with the same result.

Thanks!

[solskogen]

Any special reason why you use linux-aarch64 and not linux-rpi kernel?

[greyltc]

Why do you ask? I should expect mainline to have vc4 and KMS support by now, right? I've tried both sets of install instructions shown onmake_clickable_callback(MAGIC_URL_FULL, ' ', 'https://archlinuxarm.org/platforms/armv8/broadcom/raspberry-pi-4', '', ' class="postlink"') and in both cases I'm getting black screens unless I use nomodeset. Anyone know why that might be?

[darksky]

Your situation may be different as I never boot the upstream kernel with uboot and it has been over a year since I tested the upstream kernel when they added vc4-kms-v3d. At that time I was getting the black screen like you and I had to add cma=512M to my cmdline.txt which would be in your kernel boot parameters.

I also added snd_bcm2835.enable_headphones=1 so I could also have headphone support.

[greyltc]

Thanks, I'll try using cma=512 instead of nomodeset and report back here!

[solskogen]

the linux-aarch64 is from april (6.2.10 as this time of writing), so I would rather use linux-rpi kernel. It should work out of the box.

[graysky]

Highly recommend running the linux-rpi package on RPi hardware.

[darksky]

I am in agreement with the others here. The RPi kernel is the best kernel. They only do support for their devices and does it well. Plus there is a huge community support. It takes a long time for upstream to offer new features if they do at all.

The last time I booted the upstream kernel to test their new v3d addition it seemed to be ok but running kodi-rpi with HW decoding was a no go. The HW decoding is the one thing that is important to me as I am a big movie fan. Since firefox 116 came out with pi4 v4l2m2m h264 HW decoding I am testing youtube with the enhanched-h264iy firefox plugin and it seems to be doing ok playing mp4 videos.

Look at the difference playing the jellyfish-40-mbps-hd-hevc-10bit-mkv test video. Notice the cpu %, speed, and temp playing with mpv using SW and HW decoding on my pi400 on htop.

SW v4l2m2m decoding:make_clickable_callback(MAGIC_URL_FULL, '
', 'https://drive.google.com/file/d/11gDp0xeo8SyyZl-F4YLVYkaFdrPa3AsZ/view?usp=sharing', '', ' class="postlink"')

HW v4l2m2m decodingmake_clickable_callback(MAGIC_URL_FULL, '
', 'https://drive.google.com/file/d/1Fi1oRx7Jc-yuk9epKLzEtqhcBEKC1jzF/view?usp=sharing', '', ' class="postlink"')