drm/msm/dpu: ensure device suspend happens during PM sleep
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Message ID 1585559008-12705-1-git-send-email-kalyan_t@codeaurora.org
State New
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Series
  • drm/msm/dpu: ensure device suspend happens during PM sleep
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Commit Message

Kalyan Thota March 30, 2020, 9:03 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.

Changes in v1:
 - Remove unnecessary checks in the function
   _dpu_kms_disable_dpu (Rob Clark).

Changes in v2:
 - Avoid using suspend_late to reset the usagecount
   as suspend_late might not be called during suspend
   call failures (Doug).

Signed-off-by: Kalyan Thota <kalyan_t@codeaurora.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 33 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/msm_drv.c           |  4 ++++
 drivers/gpu/drm/msm/msm_kms.h           |  2 ++
 3 files changed, 39 insertions(+)

Comments

Kalyan Thota March 31, 2020, 2:05 p.m. UTC | #1
On 2020-03-31 00:25, Doug Anderson wrote:
> Hi,
> 
> On Mon, Mar 30, 2020 at 2:04 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.
>> 
>> Changes in v1:
>>  - Remove unnecessary checks in the function
>>    _dpu_kms_disable_dpu (Rob Clark).
>> 
>> Changes in v2:
>>  - Avoid using suspend_late to reset the usagecount
>>    as suspend_late might not be called during suspend
>>    call failures (Doug).
>> 
>> Signed-off-by: Kalyan Thota <kalyan_t@codeaurora.org>
>> ---
>>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 33 
>> +++++++++++++++++++++++++++++++++
>>  drivers/gpu/drm/msm/msm_drv.c           |  4 ++++
>>  drivers/gpu/drm/msm/msm_kms.h           |  2 ++
>>  3 files changed, 39 insertions(+)
> 
> I am still 100% baffled by your patch and I never did quite understand
> your response to my previous comments [1].  I think you're saying that
> the problem you were facing is that if you call "suspend" but never
> called "runtime_suspend" that the device stays active.  Is that right?
>  If that's true, did you try something like this suggestion I made?
> 
> SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, 
> pm_runtime_force_resume)
> 
> 
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c 
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>> index ce19f1d..2343cbd 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"
>> @@ -325,6 +326,37 @@ 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 dpu_kms *dpu_kms = to_dpu_kms(kms);
>> +       struct drm_device *dev = dpu_kms->dev;
>> +       struct msm_drm_private *priv = dev->dev_private;
>> +       struct msm_dsi *dsi;
>> +       int i;
>> +
>> +       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);
>> +       }
>> +       pm_runtime_put_sync(dev->dev);
>> +
>> +       /* Increment the usagecount without triggering a resume */
>> +       pm_runtime_get_noresume(dev->dev);
>> +
>> +       pm_runtime_get_noresume(&dpu_kms->pdev->dev);
>> +
>> +       for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
>> +               if (!priv->dsi[i])
>> +                       continue;
>> +               dsi = priv->dsi[i];
>> +               pm_runtime_get_noresume(&dsi->pdev->dev);
>> +       }
>> +}
> 
> My pm_runtime knowledge is pretty weak sometimes, but the above
> function looks crazy.  Maybe it's just me not understanding, but can
> you please summarize what you're trying to accomplish?
> 
-- I was trying to get the runtime callbacks via controlling the device 
usage_count
Since the usage_count was already incremented by PM core, i was 
decrementing and incrementing (without resume)
so that callbacks are triggered.

I have taken your suggestion on forcing the suspend instead of managing 
it via usage_count.
i'll follow it up in the next patchset.

> -Doug
> 
> [1] 
> https://lore.kernel.org/r/114130f68c494f83303c51157e2c5bfa@codeaurora.org
> _______________________________________________
> Freedreno mailing list
> Freedreno@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/freedreno

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 ce19f1d..2343cbd 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"
@@ -325,6 +326,37 @@  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 dpu_kms *dpu_kms = to_dpu_kms(kms);
+	struct drm_device *dev = dpu_kms->dev;
+	struct msm_drm_private *priv = dev->dev_private;
+	struct msm_dsi *dsi;
+	int i;
+
+	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);
+	}
+	pm_runtime_put_sync(dev->dev);
+
+	/* Increment the usagecount without triggering a resume */
+	pm_runtime_get_noresume(dev->dev);
+
+	pm_runtime_get_noresume(&dpu_kms->pdev->dev);
+
+	for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
+		if (!priv->dsi[i])
+			continue;
+		dsi = priv->dsi[i];
+		pm_runtime_get_noresume(&dsi->pdev->dev);
+	}
+}
+
 static ktime_t dpu_kms_vsync_time(struct msm_kms *kms, struct drm_crtc *crtc)
 {
 	struct drm_encoder *encoder;
@@ -751,6 +783,7 @@  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)
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 7d985f8..bb11e00 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -1040,6 +1040,7 @@  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);
@@ -1051,6 +1052,9 @@  static int msm_pm_suspend(struct device *dev)
 		return ret;
 	}
 
+	if (kms->funcs->disable_dpu)
+		kms->funcs->disable_dpu(kms);
+
 	return 0;
 }
 
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;