loader: Add support for USB devices

Allow USB devices to be used as output slaves for PRIME. Note that this
currently doesn't work on the X.Org server's built-in modesetting driver
because it requires glamor in order to expose the necessary capabilities
through RandR.

It should be possible to use this in order to accelerate Wayland clients
on the GPU, though it's questionable how useful that is without having a
compositor that gets accelerated.

Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/loader/loader.c b/src/loader/loader.c
index 9ea8c89c16b..280a60e5b9d 100644
--- a/src/loader/loader.c
+++ b/src/loader/loader.c
@@ -231,6 +231,11 @@ static char *drm_construct_id_path_tag(drmDevicePtr device)
                    device->businfo.pci->func) < 0) {
          return NULL;
       }
+   } else if (device->bustype == DRM_BUS_USB) {
+      if (asprintf(&tag, "usb-%03u_%03u", device->businfo.usb->bus,
+                   device->businfo.usb->dev) < 0) {
+         return NULL;
+      }
    } else if (device->bustype == DRM_BUS_PLATFORM ||
               device->bustype == DRM_BUS_HOST1X) {
       char *fullname, *name, *address;