Unable to map DMABUF exported memory to CPU visible buffer: Permission denied

[thesword53]

Many projects, such as Venus (vulkan implementation invirglrenderer), Wayland compositors, map dma-buf in system memory and don’t work properly or at all.

• Cursor is invisible on every wlroots based compositors.
• Venus fails to create swapchains with NVIDIA GPU (#524) · Issues · virgl / virglrenderer · GitLab

Intel and AMD drivers support that even on dedicated GPUs.

[thesword53]

That feature was added in the 565.57.01 driver but some GPU models are still unable to mmap DMA-BUF:

Mmap'ing fails with RTX 2080 SUPER (desktop) but works with GTX 1060 (laptop) and 565.57.01 drivers

The 565.57.01 driver added the possibility of mmap’ing dmabuf according to the changelog. It works with my laptop with has a GTX 1060 (Pascal) but with my desktop PC (RTX 2080, Turing), I can’t get it working with neither GSP on, off and with the open source driver. dmesg logs (open source driver): [ 96.181008] NVRM: nvAssertFailedNoLog: Assertion failed: 0 @ mapping_cpu.c:127 [ 96.181018] NVRM: nvAssertOkFailedNoLog: Assertion failed: Call not supported [NV_ERR_NOT_SUPPORTED] (0x00000056)…