[vlc-devel] [PATCH v4] linux: kernel mode setting (KMS) vout plugin

[Juha-Pekka Heikkila]

On 26.06.2018 16:08, Thomas Guillem wrote:
> Hello,
> 
> This plugin is well written. This is a very good start for DRM support into VLC. Personally, I would love to have OpenGL support with DRM, by using our OpenGL vout with a DRM window plugin and the EGL DRM extension.
> 

I was earlier talking with Remi about this, I see this kind of change as 
'v3' of this plugin..as in v1 is this bare bones working on with the 
basics. If there are special nuances found in some platform which I 
don't have access it will be easier to hunt down and fix problems. V2 is 
where mix in DRM features which can make a difference. At least with 
scaling done on display HW can be made gains on power usage as well as 
performance and its all totally free. V3 would be where add features 
which start to change things. Though, I still don't know what is the 
benefit of having OpenGL here? Remi tried to explain it to me but I 
understood from him the gain is limited because DRM is full screen only.

> I was able to test it and have one remarks:
> 
> Why do you set the DRM master mode (drmSetMaster()) ?
> It forces to run VLC as root. I tried to remove this part and was able to run your plugin as a normal user (with video group perm).
> 
> Maybe you should not fail if drmSetMaster fails ?
> 

I had chitty chatty with my friend who know how DRM rights management 
work and it turn out I can just drop the request for becoming drm 
master, these rights are given automatically for my process or otherwise 
I get error on one of my drm requests. This will also drop need for 
root. I still need to try on how it work out in reality.

/Juha-Pekka