As part of my adventures to implement 'DRM leases', it turns out to be easiest to just implement 'real' VK_KHR_display in mesa now, rather than a pile of ugly kludges. Because DRM leases just provide a DRM master fd with limited resource access, mesa doesn't have to care whether you provide a 'real' master or a lease.
That means all of the mesa code is separate from DRM leases, and can also be used to run applications directly on bare hardware.
The implementation of the KHR_display extension lives pretty much entirely within the common vulkan code in src/vulkan/wsi/wsi_common_display.c
The driver functions in radv simply call those functions, which means this should be 'trivial' to enable in the anv driver, but I haven't done that work.
To get the master FD into the driver, I've created a new extension, VK_KEITHP_kms_display which provides a DRM master file descriptor that the driver uses in place of creating it's own render node file descriptor. There's a bit of a dance involved in making sure we use the right driver; that could probably be improved.
There are a few bits of unimplemented functionality within the KHR_display implementation:
1) I don't dig the monitor name out of EDID. I'm thinking this should be done by the kernel and exposed as a property. It already has the code for this...
2) plane and surface capabilities are 'faked'. These expose the range of source surface sizes and positions which can be used; obviously the hardware can do a lot more than display an image at full size.
3) Planes in general. I'm exposing only a single plane per connector at this point. Obviously we'd want more.
4) bpp/depth. For now, I'm assuming depth 24, 32bpp. I think I just need a driver hook to get this out of the image; I sure don't want to try and parse the format.
I haven't rebased this in a while; it's a few revs back on master. I'm looking for general feedback and comments about the plan at this point; this is the second implementation of the code, I'm entirely willing to do at least one more to make it 'right'.
git://people.freedesktop.org/~keithp/mesa.git khr_display
There are also some simple changes in the vulkan looader (replicated in the relevant files in mesa) needed to gain access to the VK_KEITHP_kms_display extension (thanks, Vulkan, for not exposing vendor instance extensions by default)
git://people.freedesktop.org/~keithp/Vulkan-LoaderAndValidationLayers.git drm-leases