Am 21.06.19 um 13:58 schrieb Emil Velikov:
On 2019/06/21, Koenig, Christian wrote:
Am 21.06.19 um 12:53 schrieb Emil Velikov:
On 2019/06/21, Koenig, Christian wrote:
[SNIP] Well partially. That RADV broke is unfortunate, but we have done so many customized userspace stuff both based on Mesa/DDX as well as closed source components that it is just highly likely that we would break something else as well.
As an engineer I like to work with tangibles. The highly likely part is probable, but as mentioned multiple times the series allows for a _dead_ trivial way to address any such problems.
Well to clarify my concern is that this won't be so trivial.
You implemented on workaround for one specific case and it is perfectly possible that for other cases we would have to completely revert the removal of DRM_AUTH.
I would encourage you to take a closer look at my patch and point out how parcicular cases cannot be handled.
Well the last time I looked it only blocked the first call to the IOCTL.
If that is no longer the case then what is the actual difference to DRM_AUTH+DRM_ALLOW_RENDER?
In particular, that user-space will "remove" render nodes.
Yes, that is my main concern here. You basically make render nodes superfluously. That gives userspace all legitimization to also remove support for them. That is not stupid or evil or whatever, userspace would just follow the kernel design.
Do you have an example of userspace doing such an extremely silly thing? It does seem like suspect you're a couple of steps beyond overcautious, perhaps rightfully so. Maybe you've seen some closed-source user-space going crazy? Or any other projects?
The key point is that I don't think this is silly or strange or crazy at all. See the kernel defines the interface userspace can and should use.
When the kernel defines that everything will work with the primary node it is perfectly valid for userspace to drop support for the render node.
I mean why should they keep this? Just because we tell them not to do this?
From your experiense, do user-space developers care about doing (or generally do) the right thing?
No, not at all. Except for Marek and Michel they just take what works and even Marek is often short-cutting on this.
In either case, as pointed already the cat is out of the bag - has been for years, and if developers did behave as you describe them they would have "removed" render nodes already.
Currently render nodes are mandatory because they are needed for headless operation.
E.g. we have a whole bunch of customers which do transcoding with that on GPUs which don't even have a CRTC or even X running.
Regards, Christian.