linux-kernel - Re: [PATCH] drm/nouveau: fix hibernate on disabled GPU

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Message-ID: <172acaeecb4a1356549e0b8981928e59e603466d.camel@redhat.com>
Date: Thu, 06 Mar 2025 12:20:55 -0500
From: Lyude Paul <lyude@...hat.com>
To: "chr[]" <chris@...orff.com>, Danilo Krummrich <dakr@...nel.org>, David
 Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Cc: dri-devel@...ts.freedesktop.org, nouveau@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/nouveau: fix hibernate on disabled GPU

Reviewed-by: Lyude Paul <lyude@...hat.com>

I will push to drm-misc in a moment, thank you for the patch!

On Tue, 2025-03-04 at 22:08 +0100, chr[] wrote:
> Hibernate bricks the machine if a discrete GPU was disabled via
> 
> echo IGD > /sys/kernel/debug/vgaswitcheroo/switch
> 
> The freeze and thaw handler lacks checking the GPU power state,
> as suspend and resume do.
> 
> This patch add the checks and fix this issue.
> 
> Signed-off-by: chr[] <chris@...orff.com>
> ---
> I got an old MacBook having a defective nvidia GPU
> 
> So I put this in the initrd scripts to turn it off asap:
> 
> mount -t debugfs none /sys/kernel/debug
> echo IGD > /sys/kernel/debug/vgaswitcheroo/switch
> 
> which powers down the nouveau.
> 
> Suspend and resume works,
> but hibernate locks up the machine.
> 
> The handlers are not checking the GPU state.
> 
> Signed-off-by:
> ---
>  drivers/gpu/drm/nouveau/nouveau_drm.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
> index 5664c4c71faf1ced30f38d9874244db80d58194a..0958d1b940c2533bfadc29e098045db6f0170c79 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_drm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
> @@ -1079,6 +1079,10 @@ nouveau_pmops_freeze(struct device *dev)
>  {
>  	struct nouveau_drm *drm = dev_get_drvdata(dev);
>  
> +	if (drm->dev->switch_power_state == DRM_SWITCH_POWER_OFF ||
> +	    drm->dev->switch_power_state == DRM_SWITCH_POWER_DYNAMIC_OFF)
> +		return 0;
> +
>  	return nouveau_do_suspend(drm, false);
>  }
>  
> @@ -1087,6 +1091,10 @@ nouveau_pmops_thaw(struct device *dev)
>  {
>  	struct nouveau_drm *drm = dev_get_drvdata(dev);
>  
> +	if (drm->dev->switch_power_state == DRM_SWITCH_POWER_OFF ||
> +	    drm->dev->switch_power_state == DRM_SWITCH_POWER_DYNAMIC_OFF)
> +		return 0;
> +
>  	return nouveau_do_resume(drm, false);
>  }
>  
> 
> ---
> base-commit: 7eb172143d5508b4da468ed59ee857c6e5e01da6
> change-id: 20250304-nouveau-fix-hibernate-249826d427bb
> 
> Best regards,

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat

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