Hi Emil,
With our previous RFC patches to add interfaces to support GPU device enumeration support in libdrm, the udev mechanism was used. But we found that if we introduce the libudev dependency for libdrm, there will be some problem to run steam application on recent distributions (for example, Ubuntu 14.04 LTS) because of the conflict between the system libudev.so.1 (loaded by libdrm) and the libudev.so.0 (bundled in steam-runtime and loaded by steam application). There are some similar issues as mentioned in the links below. Although we can argue that it is application's problem, can we get rid of libudev for the device enumeration before Valve can make steam-runtime use system libraries by default? It is much appreciated if you can give some suggestions about how we can support device enumeration with libdrm.
https://wiki.debian.org/Steam https://github.com/ValveSoftware/steam-runtime/issues/13
Regards, Jammy