Re: [PATCH 2/2] drm/amdgpu: check the GART table before invalidating TLB

[Huang Rui <ray.huang@amd.com>]

On Mon, Feb 07, 2022 at 10:41:55AM +0800, Liu, Aaron wrote:
> Bypass group programming (utcl2_harvest) aims to forbid UTCL2 to send
> invalidation command to harvested SE/SA. Once invalidation command comes
> into harvested SE/SA, SE/SA has no response and system hang.
> 
> This patch is to add checking if the GART table is already allocated before
> invalidating TLB. The new procedure is as following:
> 1. Calling amdgpu_gtt_mgr_init() in amdgpu_ttm_init(). After this step GTT
>    BOs can be allocated, but GART mappings are still ignored.
> 2. Calling amdgpu_gart_table_vram_alloc() from the GMC code. This allocates
>    the GART backing store.
> 3. Initializing the hardware, and programming the backing store into VMID0
>    for all VMHUBs.
> 4. Calling amdgpu_gtt_mgr_recover() to make sure the table is updated with
>    the GTT allocations done before it was allocated.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>
> Signed-off-by: Aaron Liu <aaron.liu@amd.com>

Acked-by: Huang Rui <ray.huang@amd.com>

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> index 91d8207336c1..01cb89ffbd56 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> @@ -259,6 +259,9 @@ void amdgpu_gart_invalidate_tlb(struct amdgpu_device *adev)
>  {
>  	int i;
>  
> +	if (!adev->gart.ptr)
> +		return;
> +
>  	mb();
>  	amdgpu_device_flush_hdp(adev, NULL);
>  	for (i = 0; i < adev->num_vmhubs; i++)
> -- 
> 2.25.1
>