[PATCH 4/4] drm/amdgpu: fix VCE buffer placement restrictions

[Andy Furniss]

Christian König wrote:
> Leo and Andy could you two give that patch set a try?
> 
> It should fix occasional VCE fall outs when by coincident a buffers is 
> placed on a 4GB boundary.

On drm-next-4.15 vanilla the corruption like in -

https://bugs.freedesktop.org/show_bug.cgi?id=102296

is still present

On both vanilla and patched kernels "lesser" test cases work OK.

With the same test case as the bug (gstreamer encoding 500 frames 2160p 
nv12 in ram) with the patches I get

amdgpu: Not enough memory for command submission.
0:00:01.551998246  1092      0x238bd40 ERROR            vaapiencode 
gstvaapiencode.c:214:gst_vaapiencode_default_alloc_buffer: invalid 
GstVaapiCodedBuffer size (0 bytes)
0:00:01.552090124  1092      0x238bd40 ERROR            vaapiencode 
gstvaapiencode.c:332:gst_vaapiencode_push_frame: failed to allocate 
encoded buffer in system memory
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.
amdgpu: The CS has been cancelled because the context is lost.