linux-kernel - [PATCH] drm/panfrost: Fix module unload

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Message-Id: <20201030145833.29006-1-steven.price@arm.com>
Date:   Fri, 30 Oct 2020 14:58:33 +0000
From:   Steven Price <steven.price@....com>
To:     Daniel Vetter <daniel@...ll.ch>, David Airlie <airlied@...ux.ie>,
        Rob Herring <robh@...nel.org>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>
Cc:     Alyssa Rosenzweig <alyssa.rosenzweig@...labora.com>,
        Steven Price <steven.price@....com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Boris Brezillon <boris.brezillon@...labora.com>
Subject: [PATCH] drm/panfrost: Fix module unload

When unloading the call to pm_runtime_put_sync_suspend() will attempt to
turn the GPU cores off, however panfrost_device_fini() will have turned
the clocks off. This leads to the hardware locking up.

Instead don't call pm_runtime_put_sync_suspend() and instead simply mark
the device as suspended using pm_runtime_set_suspended(). And also
include this on the error path in panfrost_probe().

Fixes: aebe8c22a912 ("drm/panfrost: Fix possible suspend in panfrost_remove")
Signed-off-by: Steven Price <steven.price@....com>
---
 drivers/gpu/drm/panfrost/panfrost_drv.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 23513869500c..0ac8ad18fdc6 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -627,6 +627,7 @@ static int panfrost_probe(struct platform_device *pdev)
 err_out1:
 	pm_runtime_disable(pfdev->dev);
 	panfrost_device_fini(pfdev);
+	pm_runtime_set_suspended(pfdev->dev);
 err_out0:
 	drm_dev_put(ddev);
 	return err;
@@ -641,9 +642,9 @@ static int panfrost_remove(struct platform_device *pdev)
 	panfrost_gem_shrinker_cleanup(ddev);
 
 	pm_runtime_get_sync(pfdev->dev);
-	panfrost_device_fini(pfdev);
-	pm_runtime_put_sync_suspend(pfdev->dev);
 	pm_runtime_disable(pfdev->dev);
+	panfrost_device_fini(pfdev);
+	pm_runtime_set_suspended(pfdev->dev);
 
 	drm_dev_put(ddev);
 	return 0;
-- 
2.20.1