It seems to DRM lease a connector with 4288x2240 resolution successfully, but fails to create a swapchain later on.

Sat Nov 30 2024 15:49:38.616560 [Error] - WaylandHMDLeaseDevice::LeaseDevice_DrmFD: No libdrm.so

Sat Nov 30 2024 15:49:38.637793 [Info] - HMD deviceUUID is 1000000000
Sat Nov 30 2024 15:49:38.637816 [Info] - Tried to find direct display through Wayland: 0x7bbbd40701b6
Sat Nov 30 2024 15:49:38.637829 [Info] - Trying to match desired rate of 90.000000Hz.
Sat Nov 30 2024 15:49:38.637838 [Info] - 1 modes on display:
Sat Nov 30 2024 15:49:38.637850 [Info] -  - 0: [email protected]
Sat Nov 30 2024 15:49:38.637860 [Info] - Selected mode 0.

Sat Nov 30 2024 15:49:38.704021 [Info] - Swapchain failed to be created: fffffffd
Sat Nov 30 2024 15:49:38.704041 [Error] - CHmdWindowSDL::CreateSwapChainBufferResources - Invalid swapchain
Sat Nov 30 2024 15:49:38.704088 [Error] - CHmdWindowSDL: Failed to initialize mirror window
Sat Nov 30 2024 15:49:38.704221 [Error] - Error making window!
Sat Nov 30 2024 15:49:38.725383 [Info] - Failed to kill gpu-trace
Sat Nov 30 2024 15:49:38.725503 [Info] - Failed to initialize compositor
Sat Nov 30 2024 15:49:38.725526 [Info] - Failed to start compositor: VRInitError_Compositor_CannotConnectToDisplayServer

I got the same issue on Gentoo Linux with my Valve Index.

When starting SteamVR there are a few flickers and then the error shows:
Failed to connect to window manager. SteamVR failed to connect to the window manager. You may need to restart your session or SteamVR. (497)

SteamVR shows Headset, Controllers and Base Stations as green. When trying to ignore the error and trying to start e.g. the room setup the Headset and Controllers are showing offline and this error appears: SteamVR failed initialization with error code VRInitError_IPC_CompositorInvalidConnectResponse: "Shared IPC Compositor Invalid Connect Response (307)". Please verify SteamVR is properly installed and try again.

Restarting PC, restarting Valve Index, reinstalling Steam/SteamVR does not help.

Steam Client version: 1763795278
SteamVR version: 2.14.3 (beta branch), 2.13.7 (release branch), 2.12.14 (previous branch)

Distribution:
Gentoo Linux x86_64
6.17.8-gentoo-dist
KDE Plasma 6.5.3
Display Server: Wayland

CPU: AMD Ryzen 7 5800X (16) @ 4.85 GHz
GPU: AMD Radeon RX 6900 XT [Discrete]
Memory: 125.69 GiB
Filesystem: btrfs

SteamVR System Report:
SteamVR-2025-11-23-PM_07_35_27.txt

Hello @nexpspace, test with mesa 25.2.7. Mesa 25.3.0 has a regression starting with https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6173 which needs to be reported to and evaluated by the video driver vendor.

I downgraded media-libs/mesa to 25.2.7 and it works again! Thank you!