Allow using multiple SDMA schedulers only on GPUs where
we are allowed to do concurrent VM flushes.
This consideration is necessary because all GART windows
are mapped in VMID 0 (the kernel VMID) so each buffer
entity would flush VMID 0 concurrently.
Practically this means that we can't use multiple SDMA
engines for TTM on GFX6-8 and Navi 1x.
Fixes: 01c836788b ("drm/amdgpu: pass all the sdma scheds to amdgpu_mman")
Fixes: e4029f7a94 ("drm/amdgpu: only use working sdma schedulers for ttm")
Cc: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
a8171229bc