Am 07.03.2018 um 10:53 schrieb Michel Dänzer:
On 2018-03-07 10:47 AM, Christian König wrote:
See when I tested this the DDX and Mesa where unmodified, so both still
assumed VRAM as placement for scanout BOs, but the kernel forced scanout
BOs into GTT for testing.

So what happened was that on scanout we moved the VRAM BO to GTT and
after unpinning it on the first command submission which used the BO we
moved it back to VRAM again.

So as long as we don't want a severe performance penalty when you
combine old userspace with new kernel using a kernel parameter to force
scanout from GTT is not possible.
That means we either need to come up with a different workaround for
hardware issues transitioning between scanout from VRAM and GTT, or we
can't scan out from GTT in that case.

What exactly was the problem with the transition from VRAM to GTT?

I mean what we can rather easily do is check where the existing BO is pinned and then always pin into the same domain on page flip.

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