[BUG] Garbled graphics with libplacebo 7.349.0

[devusb]

Describe the bug When building with libplacebo 7.349.0, my chiaki-ng window looks like the attached screenshot, and is unusable. One of the messages that stands out in the (attached) log is

chiaki.gui: [libplacebo] Available surface configurations:
chiaki.gui: [libplacebo]     0: VK_FORMAT_A2B10G10R10_UNORM_PACK32       VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo]     1: VK_FORMAT_A2R10G10B10_UNORM_PACK32       VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo]     2: VK_FORMAT_B8G8R8A8_SRGB                  VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo]     3: VK_FORMAT_B8G8R8A8_UNORM                 VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo]     4: VK_FORMAT_R8G8B8A8_SRGB                  VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo]     5: VK_FORMAT_R8G8B8A8_UNORM                 VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo]     6: VK_FORMAT_R16G16B16A16_UNORM             VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo]     7: VK_FORMAT_R5G6B5_UNORM_PACK16            VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo]     8: VK_FORMAT_R16G16B16A16_SFLOAT            VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo] Picked surface configuration 6: VK_FORMAT_R16G16B16A16_UNORM + VK_COLOR_SPACE_SRGB_NONLINEAR_KHR
chiaki.gui: [libplacebo] Requested alpha compositing mode: VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR
chiaki.gui: [libplacebo] Requested surface transform: VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR
chiaki.gui: [libplacebo] Requested image count: 2 (min 4 max 0)
chiaki.gui: [libplacebo] Requested image size: 1280x720 (min 1x1 < cur -1x-1 < max 16384x16384)
chiaki.gui: [libplacebo] (Re)creating swapchain of size 1280x720
chiaki.gui: [libplacebo] (Re)creating 1280x720x0 texture with format a1rgb5: unknown
chiaki.gui: [libplacebo] Allocating 8126464 memory of type 0x1 (id 0) in heap 1: unknown
chiaki.gui: [libplacebo] Spent 0.122 ms allocating slab
VkFormat 7 is not supported

When built with libplacebo at c320f61e601caef2be081ce61138e5d51c1be21d (from here), it works normally.

Debug Log chiaki.log

To Reproduce Steps to reproduce the behavior:

1. Build chiaki-ng using libplacebo 7.349.0
2. Launch chiaki

Expected behavior chiaki-ng to launch normally.

Screenshots

Desktop (please complete the following information):

• OS: NixOS
• Version: 24.11
• Device: Steam Deck
• chiaki-ng Version 1.8.0

Additional context This is in the context of nixpkgs build. Reproduced on another system with 7900 XTX GPU as well, for what it's worth. Open to the fact that it's something with the nixpkgs build, but does work normally with previous libplacebo versions.