Hardware 3D acceleration doesn't work anymore with the latest git kernel

[Christian König]

Hi Michel,

Am 27.11.2017 um 12:02 schrieb Michel Dänzer:
> Hi Tom,
>
> On 2017-11-24 05:09 PM, Michel Dänzer wrote:
>> On 2017-11-24 03:29 PM, Christian Zigotzky wrote:
>>> Hi All,
>>>
>>> I bisected today and the first bad commit is:
>>> a4dec819c8bba6365eb893a4ca88db4dd1210110 (drm/ttm: Add helper functions
>>> to populate/map in one call (v2)) [1]
>> It can't really be that commit, since it just adds functions but doesn't
>> hook them up anywhere. Presumably it's commit
>> f7871fd19389c5f64f625a4389675d0740f0dfe4 ("drm/radeon: use new TTM
>> populate/dma map helper functions") instead, which makes the radeon
>> driver rely on ttm_populate_and_map_pages, which is just a stub
>> returning -ENOMEM when neither CONFIG_SWIOTLB nor CONFIG_INTEL_IOMMU is
>> enabled.
>>
>> I can see two possible solutions:
>>
>> 1. Make ttm_populate_and_map_pages and ttm_unmap_and_unpopulate_pages
>>     work without SWIOTLB / INTEL_IOMMU as well.
>>
>> 2. Make the drivers work without ttm_populate_and_map_pages and
>>     ttm_unmap_and_unpopulate_pages again in that case.
>>
>>
>> Solution 1 would be preferable.
> Which solution do you want to go for?

well, can somebody please explain to me why those patches actually 
result in problems?

They should have only moved code around, not cause anything like this.

Apart from that I also prefer solution 1.

Regards,
Christian.