Re: [PATCH] drm/amd: Keep display off while going into S4

[Harry Wentland <harry.wentland@amd.com>]

On 2025-03-06 13:51, Mario Limonciello wrote:
> When userspace invokes S4 the flow is:
> 
> 1) amdgpu_pmops_prepare()
> 2) amdgpu_pmops_freeze()
> 3) Create hibernation image
> 4) amdgpu_pmops_thaw()
> 5) Write out image to disk
> 6) Turn off system
> 
> Then on resume amdgpu_pmops_restore() is called.
> 
> This flow has a problem that because amdgpu_pmops_thaw() is called
> it will call amdgpu_device_resume() which will resume all of the GPU.
> 
> This includes turning the display hardware back on and discovering
> connectors again.
> 
> This is an unexpected experience for the display to turn back on.
> Adjust the flow so that during the S4 sequence display hardware is
> not turned back on.
> 
> Reported-by: Xaver Hugl <xaver.hugl@gmail.com>
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2038
> Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Acked-by: Harry Wentland <harry.wentland@amd.com>

Harry

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c           | 11 +++++++++--
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  5 +++++
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index b161daa90019..b54c4b2f3f7f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -2565,7 +2565,6 @@ static int amdgpu_pmops_freeze(struct device *dev)
>  	int r;
>  
>  	r = amdgpu_device_suspend(drm_dev, true);
> -	adev->in_s4 = false;
>  	if (r)
>  		return r;
>  
> @@ -2577,8 +2576,13 @@ static int amdgpu_pmops_freeze(struct device *dev)
>  static int amdgpu_pmops_thaw(struct device *dev)
>  {
>  	struct drm_device *drm_dev = dev_get_drvdata(dev);
> +	struct amdgpu_device *adev = drm_to_adev(drm_dev);
> +	int r;
>  
> -	return amdgpu_device_resume(drm_dev, true);
> +	r = amdgpu_device_resume(drm_dev, true);
> +	adev->in_s4 = false;
> +
> +	return r;
>  }
>  
>  static int amdgpu_pmops_poweroff(struct device *dev)
> @@ -2591,6 +2595,9 @@ static int amdgpu_pmops_poweroff(struct device *dev)
>  static int amdgpu_pmops_restore(struct device *dev)
>  {
>  	struct drm_device *drm_dev = dev_get_drvdata(dev);
> +	struct amdgpu_device *adev = drm_to_adev(drm_dev);
> +
> +	adev->in_s4 = false;
>  
>  	return amdgpu_device_resume(drm_dev, true);
>  }
> 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 6f9331fe91c3..5939796db74c 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -3431,6 +3431,11 @@ static int dm_resume(struct amdgpu_ip_block *ip_block)
>  
>  		return 0;
>  	}
> +
> +	/* leave display off for S4 sequence */
> +	if (adev->in_s4)
> +		return 0;
> +
>  	/* Recreate dc_state - DC invalidates it when setting power state to S3. */
>  	dc_state_release(dm_state->context);
>  	dm_state->context = dc_state_create(dm->dc, NULL);