[PATCH 1/2] drm/amdgpu: use CPU to update VM during GPU reset

[Christian König]

Am 25.03.24 um 06:35 schrieb Lang Yu:
> drm sched is stopped and SDMA mode is not available,
> while CPU mode worked well in such a case.
>
> Use case,
> amdgpu_do_asic_reset
> amdgpu_device_ip_late_init
> umsch_mm_late_init
> umsch_mm_test
> amdgpu_vm_init

Well big NAK to that.

The VM updates should just be scheduled and applied as soon as the GPU 
reset is completed.

The problem is rather that a GPU reset should *never* create a VM to do 
a test. During GPU reset no memory allocation whatsoever is allowed.

That's why we only do IB and ring tests with a pre-allocated memory pool 
during a GPU reset.

If the umsch_mm_test abuses the VM tests like this then please remove 
that code immediately.

Regards,
Christian.

>
> Signed-off-by: Lang Yu <Lang.Yu at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 8af3f0fd3073..af53f9cfcc40 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -2404,8 +2404,8 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>   
>   	vm->is_compute_context = false;
>   
> -	vm->use_cpu_for_update = !!(adev->vm_manager.vm_update_mode &
> -				    AMDGPU_VM_USE_CPU_FOR_GFX);
> +	vm->use_cpu_for_update = !!(amdgpu_in_reset(adev) ||
> +		adev->vm_manager.vm_update_mode & AMDGPU_VM_USE_CPU_FOR_GFX);
>   
>   	DRM_DEBUG_DRIVER("VM update mode is %s\n",
>   			 vm->use_cpu_for_update ? "CPU" : "SDMA");