Re: [PATCH] drm/radeon: allocate dummy_page without DMA32 on fail

[Christian König]

On 7/16/26 16:31, Anirudh Srinivasan wrote:
...
>>>>
>>>> What could be possible is to add a special quirk for your platform to not allocate the dummy page as DMA32 in the first place.
>>>
>>> So some kind of a whitelisted set of PCIE vendor/ID combos (with
>>> working IOMMUS?) where we fallback to non DMA32 ranges?
>>
>> No, what you are testing here is basically that display is functional and not anything else.
> 
> I think I understand this now. You're suggesting that we skip
> allocating the dummy page in this specific case.

Well that won't really work.

We had some minimal fallback to enable only CRTCs in the radeon driver but that was more or less only used to print error messages and not let people end up with a completely black desktop if HW initialization fails.

As far as I can see you can't use the driver/HW combination on this platform when DMA32 isn't available.

You could give efifb or vesafb a try, that is pretty much the same functionality as radeon without acceleration.

On the other hand what HW generation do you have? Maybe it's possible that this is something newer like SI or CIK? In that case you could try the more modern amdgpu driver, it should be able to better deal with the situation.

Regards,
Christian.

> 
>>
>> Regards,
>> Christian.
>>
>>>
>>> Regards
>>> Anirudh Srinivasan
>>