[PATCH] amdgpu/pm/legacy: fix suspend/resume issues

[Lazar, Lijo]

On 2/12/2025 9:41 PM, Alex Deucher wrote:
> From: "chr[]" <chris at rudorff.com>
> 
> resume and irq handler happily races in set_power_state()
> 
> * amdgpu_legacy_dpm_compute_clocks() needs lock
> * protect irq work handler
> * fix dpm_enabled usage
> 
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2524
> Fixes: 3712e7a49459 ("drm/amd/pm: unified lock protections in amdgpu_dpm.c")
> Signed-off-by: chr[] <chris at rudorff.com>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c    | 19 ++++++++++++++----
>  .../gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c    |  2 ++
>  drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c    | 20 +++++++++++++++----
>  3 files changed, 33 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
> index 67a8e22b1126d..db0d3d4dba685 100644
> --- a/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
> @@ -3042,6 +3042,7 @@ static int kv_dpm_hw_init(struct amdgpu_ip_block *ip_block)
>  	if (!amdgpu_dpm)
>  		return 0;
>  
> +	mutex_lock(&adev->pm.mutex);
>  	kv_dpm_setup_asic(adev);
>  	ret = kv_dpm_enable(adev);
>  	if (ret)
> @@ -3049,6 +3050,8 @@ static int kv_dpm_hw_init(struct amdgpu_ip_block *ip_block)
>  	else
>  		adev->pm.dpm_enabled = true;
>  	amdgpu_legacy_dpm_compute_clocks(adev);
> +	mutex_unlock(&adev->pm.mutex);
> +
>  	return ret;
>  }
>  
> @@ -3067,10 +3070,13 @@ static int kv_dpm_suspend(struct amdgpu_ip_block *ip_block)
>  	struct amdgpu_device *adev = ip_block->adev;
>  
>  	if (adev->pm.dpm_enabled) {
> +		mutex_lock(&adev->pm.mutex);
> +		adev->pm.dpm_enabled = false;
>  		/* disable dpm */
>  		kv_dpm_disable(adev);
>  		/* reset the power state */
>  		adev->pm.dpm.current_ps = adev->pm.dpm.requested_ps = adev->pm.dpm.boot_ps;
> +		mutex_unlock(&adev->pm.mutex);
>  	}
>  	return 0;
>  }
> @@ -3080,18 +3086,23 @@ static int kv_dpm_resume(struct amdgpu_ip_block *ip_block)
>  	int ret;
>  	struct amdgpu_device *adev = ip_block->adev;
>  
> -	if (adev->pm.dpm_enabled) {
> +	if (!amdgpu_dpm)
> +		return 0;
> +
> +	if (!adev->pm.dpm_enabled) {
> +		mutex_lock(&adev->pm.mutex);
>  		/* asic init will reset to the boot state */
>  		kv_dpm_setup_asic(adev);
>  		ret = kv_dpm_enable(adev);
>  		if (ret)
>  			adev->pm.dpm_enabled = false;

Need braces here as well since else part is with braces.
> -		else
> +		else {
>  			adev->pm.dpm_enabled = true;
> -		if (adev->pm.dpm_enabled)
>  			amdgpu_legacy_dpm_compute_clocks(adev);
> +		}
> +		mutex_unlock(&adev->pm.mutex);
>  	}
> -	return 0;
> +	return ret;

Possibility of returning unintialized value.

>  }
>  
>  static bool kv_dpm_is_idle(void *handle)
> diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
> index e861355ebd75b..e06c25c945007 100644
> --- a/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c
> @@ -1012,6 +1012,7 @@ void amdgpu_dpm_thermal_work_handler(struct work_struct *work)
>  	if (!adev->pm.dpm_enabled)
>  		return;
>  
> +	mutex_lock(&adev->pm.mutex);

I think taking this lock should happen before the dpm_enabled variable
check. Otherwise, it could happen that part of this sequence might still
go through after a kv/si_dpm_suspend.

>  	if (!pp_funcs->read_sensor(adev->powerplay.pp_handle,
>  				   AMDGPU_PP_SENSOR_GPU_TEMP,
>  				   (void *)&temp,
> @@ -1033,4 +1034,5 @@ void amdgpu_dpm_thermal_work_handler(struct work_struct *work)
>  	adev->pm.dpm.state = dpm_state;
>  
>  	amdgpu_legacy_dpm_compute_clocks(adev->powerplay.pp_handle);
> +	mutex_unlock(&adev->pm.mutex);
>  }
> diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
> index a87dcf0974bc1..c40ec4f74afb0 100644
> --- a/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/legacy-dpm/si_dpm.c
> @@ -7786,6 +7786,7 @@ static int si_dpm_hw_init(struct amdgpu_ip_block *ip_block)
>  	if (!amdgpu_dpm)
>  		return 0;
>  
> +	mutex_lock(&adev->pm.mutex);
>  	si_dpm_setup_asic(adev);
>  	ret = si_dpm_enable(adev);
>  	if (ret)
> @@ -7793,6 +7794,7 @@ static int si_dpm_hw_init(struct amdgpu_ip_block *ip_block)
>  	else
>  		adev->pm.dpm_enabled = true;
>  	amdgpu_legacy_dpm_compute_clocks(adev);
> +	mutex_unlock(&adev->pm.mutex);
>  	return ret;
>  }
>  
> @@ -7811,11 +7813,15 @@ static int si_dpm_suspend(struct amdgpu_ip_block *ip_block)
>  	struct amdgpu_device *adev = ip_block->adev;
>  
>  	if (adev->pm.dpm_enabled) {
> +		mutex_lock(&adev->pm.mutex);
> +		adev->pm.dpm_enabled = false;
>  		/* disable dpm */
>  		si_dpm_disable(adev);
>  		/* reset the power state */
>  		adev->pm.dpm.current_ps = adev->pm.dpm.requested_ps = adev->pm.dpm.boot_ps;
> +		mutex_unlock(&adev->pm.mutex);
>  	}
> +
>  	return 0;
>  }
>  
> @@ -7824,18 +7830,24 @@ static int si_dpm_resume(struct amdgpu_ip_block *ip_block)
>  	int ret;
>  	struct amdgpu_device *adev = ip_block->adev;
>  
> -	if (adev->pm.dpm_enabled) {
> +	if (!amdgpu_dpm)
> +		return 0;
> +
> +	if (!adev->pm.dpm_enabled) {
>  		/* asic init will reset to the boot state */
> +		mutex_lock(&adev->pm.mutex);
>  		si_dpm_setup_asic(adev);
>  		ret = si_dpm_enable(adev);
>  		if (ret)
>  			adev->pm.dpm_enabled = false;

Same 'braces' comment.

> -		else
> +		else {
>  			adev->pm.dpm_enabled = true;
> -		if (adev->pm.dpm_enabled)
>  			amdgpu_legacy_dpm_compute_clocks(adev);
> +		}
> +		mutex_unlock(&adev->pm.mutex);
>  	}
> -	return 0;
> +
> +	return ret;

Possibility of returning unintialized value.

Thanks,
Lijo

>  }
>  
>  static bool si_dpm_is_idle(void *handle)