[PATCH v2 0/4] drm/msm/adreno: fix runtime PM imbalance at unbind

[PATCH v2 0/4] drm/msm/adreno: fix runtime PM imbalance at unbind

[Johan Hovold]

As reported by Bjorn, we can end up with an unbalanced runtime PM
disable count if unbind() is called before the DRM device is opened
(e.g. if component bind fails due to the panel driver not having been
loaded yet).

As runtime PM must currently stay disabled until the firmware has been
loaded, fix this by making the runtime PM disable call at unbind()
conditional.

The rest of the series fixes further imbalances in the load_gpu() error
paths and removes a bogus pm_runtime_set_active() call. Included is also
a related indentation cleanup.

Johan


Changes in v2
 - fix the runtime PM imbalance in the gpu load error paths (new)

 - drop the patch removing the pm_runtime_disable() from
   adreno_gpu_cleanup() as this function can currently still be called
   with runtime PM enabled if suspending the scheduler in
   adreno_system_suspend() at unbind fails


Johan Hovold (4):
  drm/msm/adreno: fix runtime PM imbalance at unbind
  drm/msm/adreno: fix runtime PM imbalance at gpu load
  drm/msm/adreno: drop bogus pm_runtime_set_active()
  drm/msm/adreno: clean up component ops indentation

 drivers/gpu/drm/msm/adreno/adreno_device.c | 26 +++++++++++++---------
 1 file changed, 16 insertions(+), 10 deletions(-)

-- 
2.39.2

[PATCH v2 1/4] drm/msm/adreno: fix runtime PM imbalance at unbind

[Johan Hovold]

A recent commit moved enabling of runtime PM from adreno_gpu_init() to
adreno_load_gpu() (called on first open()), which means that unbind()
may now be called with runtime PM disabled in case the device was never
opened in between.

Make sure to only forcibly suspend and disable runtime PM at unbind() in
case runtime PM has been enabled to prevent a disable count imbalance.

This specifically avoids leaving runtime PM disabled when the device
is later opened after a successful bind:

	msm_dpu ae01000.display-controller: [drm:adreno_load_gpu [msm]] *ERROR* Couldn't power up the GPU: -13

Fixes: 4b18299b3365 ("drm/msm/adreno: Defer enabling runpm until hw_init()")
Reported-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Link: https://lore.kernel.org/lkml/20230203181245.3523937-1-quic_bjorande@quicinc.com
Cc: stable@vger.kernel.org	# 6.0
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/gpu/drm/msm/adreno/adreno_device.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
index 36f062c7582f..c5c4c93b3689 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -558,7 +558,8 @@ static void adreno_unbind(struct device *dev, struct device *master,
 	struct msm_drm_private *priv = dev_get_drvdata(master);
 	struct msm_gpu *gpu = dev_to_gpu(dev);
 
-	WARN_ON_ONCE(adreno_system_suspend(dev));
+	if (pm_runtime_enabled(dev))
+		WARN_ON_ONCE(adreno_system_suspend(dev));
 	gpu->funcs->destroy(gpu);
 
 	priv->gpu_pdev = NULL;
-- 
2.39.2

[PATCH v2 2/4] drm/msm/adreno: fix runtime PM imbalance at gpu load

[Johan Hovold]

A recent commit moved enabling of runtime PM to GPU load time (first
open()) but failed to update the error paths so that runtime PM is
disabled if initialisation of the GPU fails. This would trigger a
warning about the unbalanced disable count on the next open() attempt.

Note that pm_runtime_put_noidle() is sufficient to balance the usage
count when pm_runtime_put_sync() fails (and is chosen over
pm_runtime_resume_and_get() for consistency reasons).

Fixes: 4b18299b3365 ("drm/msm/adreno: Defer enabling runpm until hw_init()")
Cc: stable@vger.kernel.org      # 6.0
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/gpu/drm/msm/adreno/adreno_device.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
index c5c4c93b3689..f9a0b11c2e43 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -443,20 +443,21 @@ struct msm_gpu *adreno_load_gpu(struct drm_device *dev)
 
 	ret = pm_runtime_get_sync(&pdev->dev);
 	if (ret < 0) {
-		pm_runtime_put_sync(&pdev->dev);
+		pm_runtime_put_noidle(&pdev->dev);
 		DRM_DEV_ERROR(dev->dev, "Couldn't power up the GPU: %d\n", ret);
-		return NULL;
+		goto err_disable_rpm;
 	}
 
 	mutex_lock(&gpu->lock);
 	ret = msm_gpu_hw_init(gpu);
 	mutex_unlock(&gpu->lock);
-	pm_runtime_put_autosuspend(&pdev->dev);
 	if (ret) {
 		DRM_DEV_ERROR(dev->dev, "gpu hw init failed: %d\n", ret);
-		return NULL;
+		goto err_put_rpm;
 	}
 
+	pm_runtime_put_autosuspend(&pdev->dev);
+
 #ifdef CONFIG_DEBUG_FS
 	if (gpu->funcs->debugfs_init) {
 		gpu->funcs->debugfs_init(gpu, dev->primary);
@@ -465,6 +466,13 @@ struct msm_gpu *adreno_load_gpu(struct drm_device *dev)
 #endif
 
 	return gpu;
+
+err_put_rpm:
+	pm_runtime_put_sync(&pdev->dev);
+err_disable_rpm:
+	pm_runtime_disable(&pdev->dev);
+
+	return NULL;
 }
 
 static int find_chipid(struct device *dev, struct adreno_rev *rev)
-- 
2.39.2

[PATCH v2 3/4] drm/msm/adreno: drop bogus pm_runtime_set_active()

[Johan Hovold]

The runtime PM status can only be updated while runtime PM is disabled.

Drop the bogus pm_runtime_set_active() call that was made after enabling
runtime PM and which (incidentally but correctly) left the runtime PM
status set to 'suspended'.

Fixes: 2c087a336676 ("drm/msm/adreno: Load the firmware before bringing up the hardware")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/gpu/drm/msm/adreno/adreno_device.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
index f9a0b11c2e43..d9100e3870bc 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -438,9 +438,6 @@ struct msm_gpu *adreno_load_gpu(struct drm_device *dev)
 	 */
 	pm_runtime_enable(&pdev->dev);
 
-	/* Make sure pm runtime is active and reset any previous errors */
-	pm_runtime_set_active(&pdev->dev);
-
 	ret = pm_runtime_get_sync(&pdev->dev);
 	if (ret < 0) {
 		pm_runtime_put_noidle(&pdev->dev);
-- 
2.39.2

[PATCH v2 4/4] drm/msm/adreno: clean up component ops indentation

[Johan Hovold]

Clean up the component ops initialisers which were indented one level
too far.

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/gpu/drm/msm/adreno/adreno_device.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
index d9100e3870bc..f2cdc5ad7ce7 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -571,8 +571,8 @@ static void adreno_unbind(struct device *dev, struct device *master,
 }
 
 static const struct component_ops a3xx_ops = {
-		.bind   = adreno_bind,
-		.unbind = adreno_unbind,
+	.bind   = adreno_bind,
+	.unbind = adreno_unbind,
 };
 
 static void adreno_device_register_headless(void)
-- 
2.39.2

Re: [PATCH v2 0/4] drm/msm/adreno: fix runtime PM imbalance at unbind

[Johan Hovold]

On Fri, Mar 03, 2023 at 05:48:03PM +0100, Johan Hovold wrote:
> As reported by Bjorn, we can end up with an unbalanced runtime PM
> disable count if unbind() is called before the DRM device is opened
> (e.g. if component bind fails due to the panel driver not having been
> loaded yet).
> 
> As runtime PM must currently stay disabled until the firmware has been
> loaded, fix this by making the runtime PM disable call at unbind()
> conditional.
> 
> The rest of the series fixes further imbalances in the load_gpu() error
> paths and removes a bogus pm_runtime_set_active() call. Included is also
> a related indentation cleanup.

I noticed that Rob picked up the first patch below from v1 of this
series. Any comments to the remaining three?

Johan

> Changes in v2
>  - fix the runtime PM imbalance in the gpu load error paths (new)
> 
>  - drop the patch removing the pm_runtime_disable() from
>    adreno_gpu_cleanup() as this function can currently still be called
>    with runtime PM enabled if suspending the scheduler in
>    adreno_system_suspend() at unbind fails
> 
> 
> Johan Hovold (4):
>   drm/msm/adreno: fix runtime PM imbalance at unbind
>   drm/msm/adreno: fix runtime PM imbalance at gpu load
>   drm/msm/adreno: drop bogus pm_runtime_set_active()
>   drm/msm/adreno: clean up component ops indentation
> 
>  drivers/gpu/drm/msm/adreno/adreno_device.c | 26 +++++++++++++---------
>  1 file changed, 16 insertions(+), 10 deletions(-)