[2/2] drm/ttm: make TT creation purely optional v3

[Michel Dänzer]

On 2020-06-29 5:19 p.m., Christian König wrote:
> We only need the page array when the BO is about to be accessed.
> 
> So not only populate, but also create it on demand.
> 
> v2: move NULL check into ttm_tt_create()
> v3: fix the occurrence in ttm_bo_kmap_ttm as well

This broke amdgpu userptr functionality for me, in particular all
GL_AMD_pinned_memory piglit tests, e.g.

.../piglit/bin/amd_pinned_memory decrement-offset -auto -fbo
Offset is decremented, no wait.
Mesa: User error: GL_INVALID_OPERATION in glBufferData
[...]
Unexpected GL error: GL_INVALID_OPERATION 0x502
(Error at tests/spec/amd_pinned_memory/test.c:214)
PIGLIT: {"result": "fail" }


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