dumb BOs and prime

[Rob Herring]

I'm working on getting Android working with DRM drivers. ATM, I'm
using virtio-gpu as the driver and trying to get just KMS side working
without rendering. I have it working with stock AOSP and the emulated
fb with a few additions to the virtio-gpu driver[1]. Now I'm trying to
get things working with native KMS using drm_gralloc and
drm_hwcomposer (now in AOSP). I've hit one problem though which I'm
not sure how to solve without hacking around it.

Is prime allowed on dumb BOs? AIUI, dumb buffer allocation is not
allowed on render nodes and drmPrimeHandleToFD is not allowed on
card0, so I'm stuck. I could open both nodes, but then I want the case
of no render node to work. After some searching, I thought it was a
matter of needing to do drmAuthMagic, but then found that is
considered obsolete[2].

Rob

[1] git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git android-4.4
[2] http://www.x.org/wiki/Events/XDC2013/XDC2013DavidHerrmannDRMSecurity/slides.pdf