virtio-gpu-wddm-dod
virtio-gpu-wddm-dod copied to clipboard
High resolutions (4K and beyond) result in a black screen
Environment:
- M1 Pro 14" MBP
- external 4K display
- UTM 4.0.9
- latest Spice Guest Tools from here
- macOS Ventura host
- Windows 11 ARM64 guest (I checked on both 21H2 and 22H2; I have no idea whether the bug happens on x86_64 as well or not)
- any virtio display device configured for the guest (either 3D accelerated or not, it doesn't matter)
- Retina Mode enabled in GUI might make it easier to reproduce
When I resize the Windows guest's display to any resolution up to 3840x2048 (which is exactly 7.5*1024*1024 pixels - not sure if that's relevant), I have a clear display, but if I try to go any bigger (which unfortunately includes standard 4K, i.e. 3840x2160), the whole VM window goes black and only the mouse cursor is rendered properly.
Note that a Linux (Ubuntu 22.04 to be precise) guest with identical VM config works fine at 4K and beyond (I tried 6720x3780 and it's fine), so I'm pretty sure this is indeed an issue with the Windows driver.
This is still better than the upstream virtio driver which seems to be limited to 16MiB framebuffer, which would cap it around ~1500p, but not being able to run Windows full screen on a 4K display at a native resolution feels somewhat limiting. Even worse, this bug is also triggered when trying to maximize the Windows VM on the MBP's internal display in Retina mode, when the display is set to "More space" - the framebuffer is then, excluding the notch area, 3600x2250, which is still above that apparent 7.5 mebipixel limit.