linux-kernel - [PATCH v2] drm/nouveau: fix hibernate on disabled GPU

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Message-Id: <20250325-nouveau-fix-hibernate-v2-1-2bd5c13fb953@rudorff.com>
Date: Tue, 25 Mar 2025 13:44:36 +0100
From: Christoph Rudorff <chris@...orff.com>
To: Lyude Paul <lyude@...hat.com>
Cc: dri-devel@...ts.freedesktop.org, nouveau@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org, Christoph Rudorff <chris@...orff.com>
Subject: [PATCH v2] drm/nouveau: fix hibernate on disabled GPU

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: Christoph Rudorff <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.

This is a good candidate for backport.
This patch applies down to 6.12.y
---
Changes in v2:
- EDITME: use my real name, my nick raised bugs
- Link to v1: https://lore.kernel.org/r/20250304-nouveau-fix-hibernate-v1-1-ee4433546030@rudorff.com
---
 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,
-- 
Christoph Rudorff <chris@...orff.com>