Iris driver causing graphics glitch in QEMU spice egl DMA-BUF

System information

• OS: Arch Linux
• GPU: Intel Corporation Iris Plus Graphics 640 [8086:5926] (rev 06)
• Kernel version: 5.5.10-zen1-1-zen
• Mesa version: 20.0.2
• Xserver version (if applicable): 1.20.7
• Desktop manager and compositor: Plasma

Describe the issue

Graphics glitch when running a QEMU VM with SPICE EGL DMA-BUF under the new iris driver.

Regression

Not sure.

Screenshots/video files (if applicable)

Any extra information would be greatly appreciated

It is able to work around this issue by starting QEMU with i965, see: https://github.com/intel/gvt-linux/issues/142

GVT-g configuration guide: https://wiki.archlinux.org/index.php/Intel_GVT-g