Am 11.10.22 um 17:20 schrieb Simon Ser:
On Tuesday, October 11th, 2022 at 13:56, Christian König <ckoenig.leichtzumerken@xxxxxxxxx> wrote:
Am 11.10.22 um 13:37 schrieb Simon Ser:
On Tuesday, October 11th, 2022 at 13:04, Christian König ckoenig.leichtzumerken@xxxxxxxxx wrote:
we already have quite a bunch of devices which are essentially render
only and don't expose any connectors or more general display functionality.
Just recently I ran into a case where an older X/DDX combination
caused problems for such a device so I looked a bit into the
possibility to allow drivers to disable the primary node and only
expose the render node.
It turned out that this effectively hides the device from X, but
OpenGL and Vulkan can still use it perfectly fine.
The only crux is that this is checked so early in the initialization
that drivers don't have an opportunity to update their
dev->driver_features. So we will always need a separate drm_driver
structure for render only devices.
Typically render-only devices still expose a primary node, but don't
expose any KMS resources on it. See drmIsKMS() in libdrm.
Primary nodes could still be used by older user-space for rendering with
legacy DRM authentication.
Yeah, and that's exactly what we try to avoid :)
But, wouldn't that regress user-space which renders using primary nodes +
DRM auth?
Yes and that is completely intentional as well. At least for new
hardware generations we shouldn't have any userspace using this any more.
DRM auth based authentication is seen as a security risk and we want to
get rid of that for render only devices (at least for the new ones).
I should probably add a wider explanation to the commit message.
Thanks,
Christian.
