V3D Vulkan: vkAllocateMemory fails with OOM on Raspberry Pi 5B 4GB (Unity 2022 games)

[Zreaptrix]

System Info

Key	Value
Device	Raspberry Pi 5B 4GB
OS	Raspberry Pi OS Bookworm (64-bit)
Kernel	6.12.62+rpt-rpi-v8
Mesa	24.2.8-1~bpo12+rpt4
GPU	V3D 7.1.7 (VideoCore VII)
BOX64	v0.4.1

Description

When running Unturned (Unity 2022.3.62f3) via BOX64 on Raspberry Pi 5B, Vulkan crashes with "Out of memory" when allocating a buffer, immediately after SteamAPI initializes. CMA memory is confirmed free at time of crash.

Error

Vulkan - Out of memory! (allocating memory for buffer)

Stack trace points to libvulkan_broadcom.so (multiple frames).

Steps to Reproduce

1. Raspberry Pi OS Bookworm 64-bit fresh install
2. Install BOX64 via Pi-Apps (box64-rpi4arm64)
3. Install Steam via Pi-Apps
4. Install Unturned (AppID 304930) via Steam
5. Launch with:

VK_ICD_FILENAMES=/usr/share/vulkan/icd.d/broadcom_icd.aarch64.json box64 ./Unturned.x86_64 -screen-width 1280 -screen-height 720 -screen-fullscreen 0

Notes

• CMA is confirmed free at time of crash (verified with watch on /proc/meminfo)
• llvmpipe works but gives ~1fps (unusable)
• Crash occurs inside libvulkan_broadcom.so itself
• Happens consistently at same point: immediately after SteamAPI_Init() calls IClientUser::BLoggedOn

Full Logs

https://gist.github.com/Zreaptrix/af46f53e2124e7e2d88d7fe29acf4fd2

[ptitSeb]

If llvmpipe works, then I don't think it's a box64 issue, but more a mesa v3d driver one (box64 just transfert the Vulkan functions calls "as-is" to the driver, there is no emulation involved with vulkan)

[Zreaptrix]

If llvmpipe works, then I don't think it's a box64 issue, but more a mesa v3d driver one (box64 just transfert the Vulkan functions calls "as-is" to the driver, there is no emulation involved with vulkan)

Okay, thanks for getting back to me. I'll see what Mesa says.