I'm a gstreamer developer and is trying to implement a video display plugin
based on DRM/KMS which is named "kmssink".
I met a problem that the kmssink will have permission issue when running with
x11 and wayland. Because these two window system will hold DRM-Master in their
life time. So I'm change the code to use control node "controlD64" for display
and file node card0 for memory management. It work really well. Video can show
on multi display with wayland and x11. But I notice that in the Linux kernel
mainline, below commit remove the control node:
Author: Daniel Vetter <daniel.vet...@ffwll.ch<mailto:daniel.vet...@ffwll.ch>>
Date: Fri Oct 28 10:10:50 2016 +0200
drm: Nerf DRM_CONTROL nodes
Looking at the ioctl permission checks I noticed that it's impossible
to import gem buffers into a control nodes, and fd2handle/handle2fd
also don't work, so no joy with dma-bufs.
The only way to do anything with a control node is by drawing stuff
into a dumb buffer and displaying that. I suspect control nodes are an
entirely unused thing, and a cursory check shows that there does not
seem to be any callers of drmOpenControl nor of the other drmOpen
functions using DRM_MODE_CONTROL.
Since I don't like dead uabi, let's remove it. But since this would be
a really big change I think it's better to start out small by simply
not registering anything. We can garbage-collect the dead code later
on, once we're sure it's really not used anywhere.
Acked-by: Dave Airlie <airl...@gmail.com<mailto:airl...@gmail.com>>
Signed-off-by: Daniel Vetter
This will have big impace on my case, and I cannot figure out how to fix this
issue. I think control node is useful, actually many users are using this node
for application development including rockchip and amlogic. details please
I'm sending this mail for require restoring control node in file system, or is
there any other way to fix my permission issue?
MPU Mulitmedia Software
No.288 ZhuYuan Road
Suzhou New District 215011, P.R.C
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