Comment 46 for bug 1904293

Same problem on my iMac.

00:02.0 VGA compatible controller: Intel Corporation Device 0d22 (rev 08) (prog-if 00 [VGA controller])
        Subsystem: Apple Inc. Device 0122
        Flags: bus master, fast devsel, latency 0, IRQ 39
        Memory at 98000000 (64-bit, non-prefetchable) [size=4M]
        Memory at 90000000 (64-bit, prefetchable) [size=128M]
        I/O ports at 2000 [size=64]
        Expansion ROM at 000c0000 [virtual] [disabled] [size=128K]
        Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
        Capabilities: [d0] Power Management version 2
        Capabilities: [a4] PCI Advanced Features
        Kernel driver in use: i915
        Kernel modules: i915