linux-kernel - Re: [PATCH v3 18/28] drm/amdgpu: move sched status check inside amdgpu_ttm_set_buffer_funcs

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Message-ID: <1afb2956-af6c-4218-83b3-85f241332ec9@amd.com>
Date: Fri, 21 Nov 2025 16:08:07 +0100
From: Christian König <christian.koenig@....com>
To: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@....com>,
 Alex Deucher <alexander.deucher@....com>, David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>
Cc: amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 18/28] drm/amdgpu: move sched status check inside
 amdgpu_ttm_set_buffer_funcs_status



On 11/21/25 11:12, Pierre-Eric Pelloux-Prayer wrote:
> It avoids duplicated code and allows to output a warning.
> 
> Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@....com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 13 ++++---------
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    |  6 ++++++
>  2 files changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 54f7c81f287b..7167db54d722 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3309,9 +3309,7 @@ static int amdgpu_device_ip_init(struct amdgpu_device *adev)
>  	if (r)
>  		goto init_failed;
>  
> -	if (adev->mman.buffer_funcs_ring &&
> -	    adev->mman.buffer_funcs_ring->sched.ready)
> -		amdgpu_ttm_set_buffer_funcs_status(adev, true);
> +	amdgpu_ttm_set_buffer_funcs_status(adev, true);
>  
>  	/* Don't init kfd if whole hive need to be reset during init */
>  	if (adev->init_lvl->level != AMDGPU_INIT_LEVEL_MINIMAL_XGMI) {
> @@ -4191,8 +4189,7 @@ static int amdgpu_device_ip_resume(struct amdgpu_device *adev)
>  
>  	r = amdgpu_device_ip_resume_phase2(adev);
>  
> -	if (adev->mman.buffer_funcs_ring->sched.ready)
> -		amdgpu_ttm_set_buffer_funcs_status(adev, true);
> +	amdgpu_ttm_set_buffer_funcs_status(adev, true);
>  
>  	if (r)
>  		return r;
> @@ -5321,8 +5318,7 @@ int amdgpu_device_suspend(struct drm_device *dev, bool notify_clients)
>  	return 0;
>  
>  unwind_evict:
> -	if (adev->mman.buffer_funcs_ring->sched.ready)
> -		amdgpu_ttm_set_buffer_funcs_status(adev, true);
> +	amdgpu_ttm_set_buffer_funcs_status(adev, true);
>  	amdgpu_fence_driver_hw_init(adev);
>  
>  unwind_userq:
> @@ -6050,8 +6046,7 @@ int amdgpu_device_reinit_after_reset(struct amdgpu_reset_context *reset_context)
>  				if (r)
>  					goto out;
>  
> -				if (tmp_adev->mman.buffer_funcs_ring->sched.ready)
> -					amdgpu_ttm_set_buffer_funcs_status(tmp_adev, true);
> +				amdgpu_ttm_set_buffer_funcs_status(tmp_adev, true);
>  
>  				r = amdgpu_device_ip_resume_phase3(tmp_adev);
>  				if (r)
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 489880b2fb8e..9024dde0c5a7 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -2233,6 +2233,12 @@ u32 amdgpu_ttm_set_buffer_funcs_status(struct amdgpu_device *adev, bool enable)
>  	    adev->mman.buffer_funcs_enabled == enable || adev->gmc.is_app_apu)
>  		return reserved_windows;
>  
> +	if ((!adev->mman.buffer_funcs_ring || !adev->mman.buffer_funcs_ring->sched.ready) &&
> +	    enable) {
> +		dev_warn(adev->dev, "Not enabling DMA transfers for in kernel use");
> +		return 0;
> +	}
> +

Only check that when enabling the functions. Could be that when disabling them we have sched.ready set to false already.

Apart from that looks good to me.

Regards,
Christian.

>  	if (enable) {
>  		struct amdgpu_ring *ring;
>  		struct drm_gpu_scheduler *sched;