Re: [PATCH 01/13] drm/amdgpu: introduce and honour DRM_FORCE_AUTH workaround

["Michel Dänzer" <michel@daenzer.net>]

On 2019-06-21 5:44 p.m., Daniel Vetter wrote:
> On Fri, Jun 21, 2019 at 05:15:22PM +0200, Michel Dänzer wrote:
>> On 2019-06-21 1:50 p.m., Daniel Vetter wrote:
>>> On Fri, Jun 21, 2019 at 1:37 PM Christian König
>>> <ckoenig.leichtzumerken@gmail.com> wrote:
>>>> Am 21.06.19 um 13:03 schrieb Daniel Vetter:
>>>>> So if you want to depracate render functionality on primary nodes, you
>>>>> _have_ to do that hiding in userspace. Or you'll break a lot of
>>>>> compositors everywhere. Just testing -amdgpu doesn't really prove
>>>>> anything here. So you won't move the larger ecosystem with this at
>>>>> all, that ship sailed.
>>>>
>>>> So what else can we do? That sounds like you suggest we should
>>>> completely drop render node functionality.
>>>>
>>>> I mean it's not my preferred option, but certainly something that
>>>> everybody could do.
>>>>
>>>> My primary concern is that we somehow need to get rid of thinks like GEM
>>>> flink and all that other crufty stuff we still have around on the
>>>> primary node (we should probably make a list of that).
>>>>
>>>> Switching everything over to render nodes just sounded like the best
>>>> alternative so far to archive that.
>>>
>>> tbh I do like that plan too, but it's a lot more work. And I think to
>>> have any push whatsoever we probably need to roll it out in gbm as a
>>> hack to keep things going. But probably not enough.
>>>
>>> I also think that at least some compositors will bother to do the
>>> right thing, and actually bother with render nodes and all that
>>> correctly. It's just that there's way more which dont.
>>
>> With amdgpu, we can make userspace always use render nodes for rendering
>> with changes to libdrm_amdgpu/radeonsi/xf86-video-amdgpu (and maybe some
>> amdgpu-pro components) only. No GBM/compositor changes needed.
> 
> This is a very non-exhaustive list of userspace that runs on your driver
> ... This wayland compositor thing, actually shipping now, and there's many :-)

You don't seem to understand what I wrote. Everything will work at least
as well as now, without any other changes.


>>>>> Once we picked a color it's a simple technical matter of how to roll
>>>>> it out, using Kconfig options, or only enabling on new hw, or "merge
>>>>> and fix the regressions as they come" or any of the other well proven
>>>>> paths forward.
>>>>
>>>> Yeah, the problem is I don't see an option which currently works for
>>>> everyone.
>>>>
>>>> I absolutely need a grace time of multiple years until we can apply this
>>>> to amdgpu/radeon.
>>>
>>> Yeah that's what I meant with "pick a color, pick a way to roll it
>>> out". "enable for new hw, roll out years and years later" is one of
>>> the options for roll out.
>>
>> One gotcha being that generic userspace such as the Xorg modesetting
>> driver may still try to use phased out functionality such as DRI2 with
>> new hardware.
> 
> There's a lot more generic userspace than -modesetting.

That is affected by phasing out DRI2 related functionality? (I thought
that was the context of this sub-sub-thread)


> That was the entire point of kms, and it succeed really well. That's
> why I don't think amdgpu doing their own flavour pick is going to help
> anyone here,
Other drivers are welcome to emulate amdgpu's design making the above
possible. :)


> except maybe if all you care about is the amd stand-alone> stack only.
> But then why do you bother with this upstream stuff at all> ...

I'm afraid you've lost me here.


-- 
Earthling Michel Dänzer               |              https://www.amd.com
Libre software enthusiast             |             Mesa and X developer
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