Re: [PATCH 1/2] drm/amdgpu/gfx11: return early in preempt_ib()

[SRINIVASAN SHANMUGAM <srinivasan.shanmugam@amd.com>]

On 8/15/2024 10:30 PM, Alex Deucher wrote:
> When MES is enabled KIQ is not available.  Return an error
> when someone uses the debugfs preempt test interface in
> that case.
>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> index 5685aee479df..5704ad25a49d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
> @@ -5924,6 +5924,9 @@ static int gfx_v11_0_ring_preempt_ib(struct amdgpu_ring *ring)
>   	struct amdgpu_ring *kiq_ring = &kiq->ring;
>   	unsigned long flags;
>   
> +	if (adev->enable_mes)
> +		return -EINVAL;
> +
>   	if (!kiq->pmf || !kiq->pmf->kiq_unmap_queues)
>   		return -EINVAL;
>   

With MES feature enabled, based on allowing multiple command streams to 
be executed concurrently on the GPU Vs KIQ that is used to send commands 
to the GPU in a sequential manner, having both of them active at the 
same time could lead to conflicts.

Therefore, when the MES is enabled, the KIQ becomes unavailable.

With this understanding, this series is:

Acked-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>