Re: [PATCH] drm/amdgpu: fix invalid fence handling in amdgpu_vm_tlb_flush

["Christian König" <christian.koenig@amd.com>]

Am 02.09.24 um 05:03 schrieb Lang Yu:
> Fixes: 5a1c27951966 ("drm/amdgpu: implement TLB flush fence")
>
> Signed-off-by: Lang Yu <lang.yu@amd.com>

Ah yes, that explains why CPU based updates doesn't work reliable any more.

You need to add some explanation to the commit message, e.g. something 
like "CPU based updates doesn't produce a fence."

With that done Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>   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 1d46a5c81ec4..f93804902fd3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -908,10 +908,12 @@ amdgpu_vm_tlb_flush(struct amdgpu_vm_update_params *params,
>   {
>   	struct amdgpu_vm *vm = params->vm;
>   
> -	if (!fence || !*fence)
> +	tlb_cb->vm = vm;
> +	if (!fence || !*fence) {
> +		amdgpu_vm_tlb_seq_cb(NULL, &tlb_cb->cb);
>   		return;
> +	}
>   
> -	tlb_cb->vm = vm;
>   	if (!dma_fence_add_callback(*fence, &tlb_cb->cb,
>   				    amdgpu_vm_tlb_seq_cb)) {
>   		dma_fence_put(vm->last_tlb_flush);