drm/msm/dpu: ensure device suspend happens during PM sleep
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Message ID 1584356720-24411-1-git-send-email-kalyan_t@codeaurora.org
State New
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  • drm/msm/dpu: ensure device suspend happens during PM sleep
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Commit Message

Kalyan Thota March 16, 2020, 11:05 a.m. UTC
"The PM core always increments the runtime usage counter
before calling the ->suspend() callback and decrements it
after calling the ->resume() callback"

DPU and DSI are managed as runtime devices. When
suspend is triggered, PM core adds a refcount on all the
devices and calls device suspend, since usage count is
already incremented, runtime suspend was not getting called
and it kept the clocks on which resulted in target not
entering into XO shutdown.

Add changes to manage runtime devices during pm sleep.

Signed-off-by: Kalyan Thota <kalyan_t@codeaurora.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 41 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/dsi/dsi.c           |  7 ++++++
 drivers/gpu/drm/msm/msm_drv.c           | 14 +++++++++++
 drivers/gpu/drm/msm/msm_kms.h           |  2 ++
 4 files changed, 64 insertions(+)

Comments

Douglas Anderson March 17, 2020, 9:38 p.m. UTC | #1
Hi,

On Mon, Mar 16, 2020 at 4:06 AM Kalyan Thota <kalyan_t@codeaurora.org> wrote:
>
> "The PM core always increments the runtime usage counter
> before calling the ->suspend() callback and decrements it
> after calling the ->resume() callback"
>
> DPU and DSI are managed as runtime devices. When
> suspend is triggered, PM core adds a refcount on all the
> devices and calls device suspend, since usage count is
> already incremented, runtime suspend was not getting called
> and it kept the clocks on which resulted in target not
> entering into XO shutdown.
>
> Add changes to manage runtime devices during pm sleep.
>
> Signed-off-by: Kalyan Thota <kalyan_t@codeaurora.org>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 41 +++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/msm/dsi/dsi.c           |  7 ++++++
>  drivers/gpu/drm/msm/msm_drv.c           | 14 +++++++++++
>  drivers/gpu/drm/msm/msm_kms.h           |  2 ++
>  4 files changed, 64 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> index cb08faf..6e103d5 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> @@ -26,6 +26,7 @@
>  #include "dpu_encoder.h"
>  #include "dpu_plane.h"
>  #include "dpu_crtc.h"
> +#include "dsi.h"
>
>  #define CREATE_TRACE_POINTS
>  #include "dpu_trace.h"
> @@ -250,6 +251,37 @@ static void dpu_kms_disable_commit(struct msm_kms *kms)
>         pm_runtime_put_sync(&dpu_kms->pdev->dev);
>  }
>
> +static void _dpu_kms_disable_dpu(struct msm_kms *kms)
> +{
> +       struct drm_device *dev;
> +       struct msm_drm_private *priv;
> +       struct dpu_kms *dpu_kms;
> +       int i = 0;
> +       struct msm_dsi *dsi;
> +
> +       dpu_kms = to_dpu_kms(kms);
> +       dev = dpu_kms->dev;
> +       if (!dev) {
> +               DPU_ERROR("invalid device\n");
> +               return;
> +       }
> +
> +       priv = dev->dev_private;
> +       if (!priv) {
> +               DPU_ERROR("invalid private data\n");
> +               return;
> +       }
> +
> +       dpu_kms_disable_commit(kms);
> +
> +       for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
> +               if (!priv->dsi[i])
> +                       continue;
> +               dsi = priv->dsi[i];
> +               pm_runtime_put_sync(&dsi->pdev->dev);
> +       }
> +}
> +
>  static ktime_t dpu_kms_vsync_time(struct msm_kms *kms, struct drm_crtc *crtc)
>  {
>         struct drm_encoder *encoder;
> @@ -683,6 +715,7 @@ static void dpu_irq_uninstall(struct msm_kms *kms)
>  #ifdef CONFIG_DEBUG_FS
>         .debugfs_init    = dpu_kms_debugfs_init,
>  #endif
> +       .disable_dpu = _dpu_kms_disable_dpu,
>  };
>
>  static void _dpu_kms_mmu_destroy(struct dpu_kms *dpu_kms)
> @@ -1053,7 +1086,15 @@ static int __maybe_unused dpu_runtime_resume(struct device *dev)
>         return rc;
>  }
>
> +
> +static int __maybe_unused dpu_pm_suspend_late(struct device *dev)
> +{
> +       pm_runtime_get_noresume(dev);
> +       return 0;
> +}
> +
>  static const struct dev_pm_ops dpu_pm_ops = {
> +       SET_LATE_SYSTEM_SLEEP_PM_OPS(dpu_pm_suspend_late, NULL)
>         SET_RUNTIME_PM_OPS(dpu_runtime_suspend, dpu_runtime_resume, NULL)
>  };
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
> index 55ea4bc2..3d3740e 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi.c
> @@ -154,12 +154,19 @@ static int dsi_dev_remove(struct platform_device *pdev)
>         return 0;
>  }
>
> +static int __maybe_unused dsi_pm_suspend_late(struct device *dev)
> +{
> +       pm_runtime_get_noresume(dev);
> +       return 0;
> +}
> +
>  static const struct of_device_id dt_match[] = {
>         { .compatible = "qcom,mdss-dsi-ctrl" },
>         {}
>  };
>
>  static const struct dev_pm_ops dsi_pm_ops = {
> +       SET_LATE_SYSTEM_SLEEP_PM_OPS(dsi_pm_suspend_late, NULL)
>         SET_RUNTIME_PM_OPS(msm_dsi_runtime_suspend, msm_dsi_runtime_resume, NULL)
>  };
>
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index e4b750b..12ec1c6 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -1038,6 +1038,7 @@ static int msm_pm_suspend(struct device *dev)
>  {
>         struct drm_device *ddev = dev_get_drvdata(dev);
>         struct msm_drm_private *priv = ddev->dev_private;
> +       struct msm_kms *kms = priv->kms;
>
>         if (WARN_ON(priv->pm_state))
>                 drm_atomic_state_put(priv->pm_state);
> @@ -1049,6 +1050,11 @@ static int msm_pm_suspend(struct device *dev)
>                 return ret;
>         }
>
> +       if (kms->funcs->disable_dpu)
> +               kms->funcs->disable_dpu(kms);
> +
> +       pm_runtime_put_sync(dev);
> +
>         return 0;
>  }
>
> @@ -1067,6 +1073,13 @@ static int msm_pm_resume(struct device *dev)
>
>         return ret;
>  }
> +
> +static int msm_pm_suspend_late(struct device *dev)
> +{
> +       pm_runtime_get_noresume(dev);
> +       return 0;
> +}
> +
>  #endif
>
>  #ifdef CONFIG_PM
> @@ -1100,6 +1113,7 @@ static int msm_runtime_resume(struct device *dev)
>  #endif
>
>  static const struct dev_pm_ops msm_pm_ops = {
> +       SET_LATE_SYSTEM_SLEEP_PM_OPS(msm_pm_suspend_late, NULL)
>         SET_SYSTEM_SLEEP_PM_OPS(msm_pm_suspend, msm_pm_resume)
>         SET_RUNTIME_PM_OPS(msm_runtime_suspend, msm_runtime_resume, NULL)
>  };
> diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h
> index 1cbef6b..c73a89b 100644
> --- a/drivers/gpu/drm/msm/msm_kms.h
> +++ b/drivers/gpu/drm/msm/msm_kms.h
> @@ -126,6 +126,8 @@ struct msm_kms_funcs {
>         /* debugfs: */
>         int (*debugfs_init)(struct msm_kms *kms, struct drm_minor *minor);
>  #endif
> +       void (*disable_dpu)(struct msm_kms *kms);
> +

I'm by no means an expert on any of this, but it seems awfully
asymmetric to me and that feels like you're going to end up with bugs.

* Is it possible that disable_dpu() will be called more than once
during normal operation, like if the screen goes off?  Will your
counts be off then?

* What happens if suspend is aborted partway through (by getting a
wakeup even as you're suspending, for instance)?  In such a case some
of the normal suspend calls will be called but "suspend_late" won't be
called.  Does that mess up your counting?


From your description, it sure seems like this part of the
runtime_pm.rst doc is relevant to you:

> Namely, if a system suspend .prepare() callback returns a positive
> number for a device, that indicates to the PM core that the device
> appears to be runtime-suspended and its state is fine, so it may
> be left in runtime suspend provided that all of its descendants
> are also left in runtime suspend.

Did I misunderstand and this isn't what you want?  Looking a bit
further, maybe the right thing is to use the "SMART_SUSPEND" flag?

I'll also note that sometimes when people just want to be Runtime PM
managed that I see this pattern:

SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)


-Doug

Patch
diff mbox series

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index cb08faf..6e103d5 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -26,6 +26,7 @@ 
 #include "dpu_encoder.h"
 #include "dpu_plane.h"
 #include "dpu_crtc.h"
+#include "dsi.h"
 
 #define CREATE_TRACE_POINTS
 #include "dpu_trace.h"
@@ -250,6 +251,37 @@  static void dpu_kms_disable_commit(struct msm_kms *kms)
 	pm_runtime_put_sync(&dpu_kms->pdev->dev);
 }
 
+static void _dpu_kms_disable_dpu(struct msm_kms *kms)
+{
+	struct drm_device *dev;
+	struct msm_drm_private *priv;
+	struct dpu_kms *dpu_kms;
+	int i = 0;
+	struct msm_dsi *dsi;
+
+	dpu_kms = to_dpu_kms(kms);
+	dev = dpu_kms->dev;
+	if (!dev) {
+		DPU_ERROR("invalid device\n");
+		return;
+	}
+
+	priv = dev->dev_private;
+	if (!priv) {
+		DPU_ERROR("invalid private data\n");
+		return;
+	}
+
+	dpu_kms_disable_commit(kms);
+
+	for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
+		if (!priv->dsi[i])
+			continue;
+		dsi = priv->dsi[i];
+		pm_runtime_put_sync(&dsi->pdev->dev);
+	}
+}
+
 static ktime_t dpu_kms_vsync_time(struct msm_kms *kms, struct drm_crtc *crtc)
 {
 	struct drm_encoder *encoder;
@@ -683,6 +715,7 @@  static void dpu_irq_uninstall(struct msm_kms *kms)
 #ifdef CONFIG_DEBUG_FS
 	.debugfs_init    = dpu_kms_debugfs_init,
 #endif
+	.disable_dpu = _dpu_kms_disable_dpu,
 };
 
 static void _dpu_kms_mmu_destroy(struct dpu_kms *dpu_kms)
@@ -1053,7 +1086,15 @@  static int __maybe_unused dpu_runtime_resume(struct device *dev)
 	return rc;
 }
 
+
+static int __maybe_unused dpu_pm_suspend_late(struct device *dev)
+{
+	pm_runtime_get_noresume(dev);
+	return 0;
+}
+
 static const struct dev_pm_ops dpu_pm_ops = {
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(dpu_pm_suspend_late, NULL)
 	SET_RUNTIME_PM_OPS(dpu_runtime_suspend, dpu_runtime_resume, NULL)
 };
 
diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
index 55ea4bc2..3d3740e 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.c
+++ b/drivers/gpu/drm/msm/dsi/dsi.c
@@ -154,12 +154,19 @@  static int dsi_dev_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static int __maybe_unused dsi_pm_suspend_late(struct device *dev)
+{
+	pm_runtime_get_noresume(dev);
+	return 0;
+}
+
 static const struct of_device_id dt_match[] = {
 	{ .compatible = "qcom,mdss-dsi-ctrl" },
 	{}
 };
 
 static const struct dev_pm_ops dsi_pm_ops = {
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(dsi_pm_suspend_late, NULL)
 	SET_RUNTIME_PM_OPS(msm_dsi_runtime_suspend, msm_dsi_runtime_resume, NULL)
 };
 
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index e4b750b..12ec1c6 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -1038,6 +1038,7 @@  static int msm_pm_suspend(struct device *dev)
 {
 	struct drm_device *ddev = dev_get_drvdata(dev);
 	struct msm_drm_private *priv = ddev->dev_private;
+	struct msm_kms *kms = priv->kms;
 
 	if (WARN_ON(priv->pm_state))
 		drm_atomic_state_put(priv->pm_state);
@@ -1049,6 +1050,11 @@  static int msm_pm_suspend(struct device *dev)
 		return ret;
 	}
 
+	if (kms->funcs->disable_dpu)
+		kms->funcs->disable_dpu(kms);
+
+	pm_runtime_put_sync(dev);
+
 	return 0;
 }
 
@@ -1067,6 +1073,13 @@  static int msm_pm_resume(struct device *dev)
 
 	return ret;
 }
+
+static int msm_pm_suspend_late(struct device *dev)
+{
+	pm_runtime_get_noresume(dev);
+	return 0;
+}
+
 #endif
 
 #ifdef CONFIG_PM
@@ -1100,6 +1113,7 @@  static int msm_runtime_resume(struct device *dev)
 #endif
 
 static const struct dev_pm_ops msm_pm_ops = {
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(msm_pm_suspend_late, NULL)
 	SET_SYSTEM_SLEEP_PM_OPS(msm_pm_suspend, msm_pm_resume)
 	SET_RUNTIME_PM_OPS(msm_runtime_suspend, msm_runtime_resume, NULL)
 };
diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h
index 1cbef6b..c73a89b 100644
--- a/drivers/gpu/drm/msm/msm_kms.h
+++ b/drivers/gpu/drm/msm/msm_kms.h
@@ -126,6 +126,8 @@  struct msm_kms_funcs {
 	/* debugfs: */
 	int (*debugfs_init)(struct msm_kms *kms, struct drm_minor *minor);
 #endif
+	void (*disable_dpu)(struct msm_kms *kms);
+
 };
 
 struct msm_kms;