Garbled rendering in Wayland on SC8180X Primus

I have a SC8180X CLS Primus prototype device, which runs MollySophia's 6.4-rc2 tree and works reasonably well.

Recently I want to upgrade to mainline kernel, and compiled the current RC with arm64_defconfig.

But with mainline the screen is garbled in Wayland, I tried both weston and kwin-wayland and had similar result. The mouse cursor renders OK though.

Both the framebuffer console and X11 renders fine, only Wayland is broken.

I don't think it is a Mesa issue since Wayland works fine on MollySophia's tree with the same userspace.

Distro is up-to-date Debian testing, and I loaded the DTB (qcom/sc8180x-primus.dtb) that came with the kernel in Grub2.