[PATCH] drm/amdgpu: Account for shadow PTs in mapping update IB size.

[Bas Nieuwenhuizen]

When amdgpu_vm_frag_ptes calls amdgpu_vm_update_ptes and the pt
has a shadow PT we mirror all the write to the shadow PT too, which
results in twice the commands.

Signed-off-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
---

The current patch is quite pessimistic, maybe someone familiar with the
code knows a better set of conditions.

 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 09811b2b89fe..22f5007d6821 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1547,10 +1547,12 @@ static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
 	nptes = last - start + 1;
 
 	/*
-	 * reserve space for one command every (1 << BLOCK_SIZE)
+	 * reserve space for two commands every (1 << BLOCK_SIZE)
 	 *  entries or 2k dwords (whatever is smaller)
+         *
+         * The second command is for the shadow pagetables.
 	 */
-	ncmds = (nptes >> min(adev->vm_manager.block_size, 11u)) + 1;
+	ncmds = ((nptes >> min(adev->vm_manager.block_size, 11u)) + 1) * 2;
 
 	/* padding, etc. */
 	ndw = 64;
-- 
2.14.1