[PATCH 2/2] drm/amdgpu: Mark ctx as guilty in ring_soft_recovery path

[Joshua Ashton]

On 1/15/24 15:25, Michel Dänzer wrote:
> On 2024-01-15 14:17, Christian König wrote:
>> Am 15.01.24 um 12:37 schrieb Joshua Ashton:
>>> On 1/15/24 09:40, Christian König wrote:
>>>> Am 13.01.24 um 15:02 schrieb Joshua Ashton:
>>>>
>>>>> Without this feedback, the application may keep pushing through the soft
>>>>> recoveries, continually hanging the system with jobs that timeout.
>>>>
>>>> Well, that is intentional behavior. Marek is voting for making soft recovered errors fatal as well while Michel is voting for better ignoring them.
>>>>
>>>> I'm not really sure what to do. If you guys think that soft recovered hangs should be fatal as well then we can certainly do this.
> 
> A possible compromise might be making soft resets fatal if they happen repeatedly (within a certain period of time?).
> 

No, no and no. Aside from introducing issues by side effects not 
surfacing and all of the stuff I mentioned about descriptor buffers, 
bda, draw indirect and stuff just resulting in more faults and hangs...

You are proposing we throw out every promise we made to an application 
on the API contract level because it "might work". That's just wrong!

Let me put this in explicit terms: What you are proposing is in direct 
violation of the GL and Vulkan specification.

You can't just chose to break these contracts because you think it 
'might' be a better user experience.

> 
>>> They have to be!
>>>
>>> As Marek and I have pointed out, applications that hang or fault will just hang or fault again, especially when they use things like draw indirect, buffer device address, descriptor buffers, etc.
>>
>> Ok, well then I now have two people (Marek and you) saying that soft recovery should be fatal while Michel is saying that soft recovery being non fatal improves stability for him :)
> 
> That's not quite what I wrote before.
> 
> I pointed out that my GNOME session has survived a soft reset without issues[0] on multiple occasions, whereas Marek's proposal at the time would have kicked me back to the login screen every time. > 0 vs effectively 0 chance of survival.

The correct thing for GNOME/Mutter to do is to simply re-create it's 
context, reimport it's DMABUFs, etc.

The fact that it survives and keeps soldiering on with whatever side 
effects missed is purely coincidental and not valid API usage.

If you want such behaviour for hangs for Mutter, you should propose a 
GL/VK extension for it, but I really doubt that will get anywhere.

- Joshie 🐸✨

> 
> [0] Except for Firefox unnecessarily falling back to software rendering, which is a side note, not the main point.
> 
>