[RFC PATCH 10/13] drm/admgpu: make device state machine work in stack like way

[Mario Limonciello]

On 1/8/2025 08:00, Jiang Liu wrote:
> Make the device state machine work in stack like way to better support
> suspend/resume by following changes:
> 
> 1. amdgpu_driver_load_kms()
> 	amdgpu_device_init()
> 		amdgpu_device_ip_early_init()
> 			ip_blocks[i].early_init()
> 			ip_blocks[i].status.valid = true
> 		amdgpu_device_ip_init()
> 			amdgpu_ras_init()
> 			ip_blocks[i].sw_init()
> 			ip_blocks[i].status.sw = true
> 			ip_blocks[i].hw_init()
> 			ip_blocks[i].status.hw = true
> 		amdgpu_device_ip_late_init()
> 			ip_blocks[i].late_init()
> 			ip_blocks[i].status.late_initialized = true
> 			amdgpu_ras_late_init()
> 				ras_blocks[i].ras_late_init()
> 					amdgpu_ras_feature_enable_on_boot()
> 
> 2. amdgpu_pmops_suspend()/amdgpu_pmops_freeze()/amdgpu_pmops_poweroff()
> 	amdgpu_device_suspend()
> 		amdgpu_ras_early_fini()
> 			ras_blocks[i].ras_early_fini()
> 				amdgpu_ras_feature_disable()
> 		amdgpu_ras_suspend()
> 			amdgpu_ras_disable_all_features()
> +++		ip_blocks[i].early_fini()
> +++		ip_blocks[i].status.late_initialized = false
> 		ip_blocks[i].suspend()
> 
> 3. amdgpu_pmops_resume()/amdgpu_pmops_thaw()/amdgpu_pmops_restore()
> 	amdgpu_device_resume()
> 		amdgpu_device_ip_resume()
> 			ip_blocks[i].resume()
> 		amdgpu_device_ip_late_init()
> 			ip_blocks[i].late_init()
> 			ip_blocks[i].status.late_initialized = true
> 			amdgpu_ras_late_init()
> 				ras_blocks[i].ras_late_init()
> 					amdgpu_ras_feature_enable_on_boot()
> 		amdgpu_ras_resume()
> 			amdgpu_ras_enable_all_features()
> 
> 4. amdgpu_driver_unload_kms()
> 	amdgpu_device_fini_hw()
> 		amdgpu_ras_early_fini()
> 			ras_blocks[i].ras_early_fini()
> +++		ip_blocks[i].early_fini()
> +++		ip_blocks[i].status.late_initialized = false
> 		ip_blocks[i].hw_fini()
> 		ip_blocks[i].status.hw = false
> 
> 5. amdgpu_driver_release_kms()
> 	amdgpu_device_fini_sw()
> 		amdgpu_device_ip_fini()
> 			ip_blocks[i].sw_fini()
> 			ip_blocks[i].status.sw = false
> ---			ip_blocks[i].status.valid = false
> +++			amdgpu_ras_fini()
> 			ip_blocks[i].late_fini()
> +++			ip_blocks[i].status.valid = false
> ---			ip_blocks[i].status.late_initialized = false
> ---			amdgpu_ras_fini()
> 
> The main changes include:
> 1) invoke ip_blocks[i].early_fini in amdgpu_pmops_suspend().
>     Currently there's only one ip block which provides `early_fini`
>     callback. We have add a check of `in_s3` to keep current behavior in
>     function amdgpu_dm_early_fini(). So there should be no functional
>     changes.

FWIW You added more than just the in_s3 (which is correct, so update 
commit message!).

> 2) set ip_blocks[i].status.late_initialized to false after calling
>     callback `early_fini`. We have auditted all usages of the
>     late_initialized flag and no functional changes found.
> 3) only set ip_blocks[i].status.valid = false after calling the
>     `late_fini` callback.
> 4) call amdgpu_ras_fini() before invoking ip_blocks[i].late_fini.
> 
> There's one more task left to analyze GPU reset related state machine
> transitions.
> 
> Signed-off-by: Jiang Liu <gerry at linux.alibaba.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c    | 22 +++++++++++++++++--
>   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  3 +++
>   2 files changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 36a33a391411..5c6b39e5cdaa 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3411,6 +3411,8 @@ static int amdgpu_device_ip_fini(struct amdgpu_device *adev)
>   		adev->ip_blocks[i].status.sw = false;
>   	}
>   
> +	amdgpu_ras_fini(adev);
> +
>   	for (i = adev->num_ip_blocks - 1; i >= 0; i--) {
>   		if (!adev->ip_blocks[i].status.valid)
>   			continue;
> @@ -3419,8 +3421,6 @@ static int amdgpu_device_ip_fini(struct amdgpu_device *adev)
>   		adev->ip_blocks[i].status.valid = false;
>   	}
>   
> -	amdgpu_ras_fini(adev);
> -
>   	return 0;
>   }
>   
> @@ -3478,6 +3478,24 @@ static int amdgpu_device_ip_suspend_phase1(struct amdgpu_device *adev)
>   	if (amdgpu_dpm_set_df_cstate(adev, DF_CSTATE_DISALLOW))
>   		dev_warn(adev->dev, "Failed to disallow df cstate");
>   
> +	for (i = adev->num_ip_blocks - 1; i >= 0; i--) {

This is the 37th time we have a for loop that walks the IP blocks.
I'm thinking it would be good to have for_each_ip_block macro, what do 
you think?

> +		if (!adev->ip_blocks[i].status.valid)
> +			continue;
> +		if (!adev->ip_blocks[i].status.late_initialized)
> +			continue;

If you take my idea in the cover letter of moving the state machine into 
a single variable I think that some of these cases can be a little bit 
cleaner.  IE if it was never valid it wouldn't have progressed to 'hw' 
or 'sw' states.

This check (and other similar ones) could turn into something like this:

if (adev->ip_blocks[i].status != AMDGPU_STATE_LATE_INIT)
	continue;

> +
> +		if (adev->ip_blocks[i].version->funcs->early_fini) {
> +			r = adev->ip_blocks[i].version->funcs->early_fini(&adev->ip_blocks[i]);
> +			if (r) {
> +				DRM_ERROR(" of IP block <%s> failed %d\n",
> +					  adev->ip_blocks[i].version->funcs->name, r);
> +				return r;
> +			}
> +		}
> +
> +		adev->ip_blocks[i].status.late_initialized = false;
> +	}
> +
>   	for (i = adev->num_ip_blocks - 1; i >= 0; i--) {
>   		if (!adev->ip_blocks[i].status.valid)
>   			continue;
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index f622eb1551df..33a1a795c761 100755
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -2175,6 +2175,9 @@ static int amdgpu_dm_early_fini(struct amdgpu_ip_block *ip_block)
>   {
>   	struct amdgpu_device *adev = ip_block->adev;
>   
> +	if (adev->in_s0ix || adev->in_s3 || adev->in_s4 || adev->in_suspend)
> +		return 0;
> +

I think this set of changes to display code (amdgpu_dm) should split to 
it's own patch and stand on it's own.

>   	amdgpu_dm_audio_fini(adev);
>   
>   	return 0;