[PATCH 2/2] drm/amdgpu: Enable clear page functionality

[Felix Kuehling]

On 2023-12-11 04:50, Christian König wrote:
> Am 08.12.23 um 20:53 schrieb Alex Deucher:
>> [SNIP]
>>> You also need a functionality which resets all cleared blocks to
>>> uncleared after suspend/resume.
>>>
>>> No idea how to do this, maybe Alex knows of hand.
>> Since the buffers are cleared on creation, is there actually anything to do?
>
> Well exactly that's the problem, the buffers are no longer always 
> cleared on creation with this patch.
>
> Instead we clear on free, track which areas are cleared and clear only 
> the ones which aren't cleared yet on creation.

The code I added for clearing-on-free a long time ago, does not clear to 
0, but to a non-0 poison value. That was meant to make it easier to 
catch applications incorrectly relying on 0-initialized memory. Is that 
being changed? I didn't see it in this patch series.

Regards,
   Felix


>
> So some cases need special handling. E.g. when the engine is not 
> initialized yet or suspend/resume.
>
> In theory after a suspend/resume cycle the VRAM is cleared to zeros, 
> but in practice that's not always true.
>
> Christian.
>
>> Alex