On Wed, Sep 13, 2023 at 03:02:58PM +0300, Jani Nikula wrote:
> On Wed, 13 Sep 2023, Jouni Högander <jouni.hogander@xxxxxxxxx> wrote:
> > It's not necessary to carry separate suspended status information in
> > intel_runtime_pm struct as this information is already in underlying device
> > structure. Remove it and use pm_runtime_suspended() to obtain suspended
> > status information when needed.
>
> I started wondering if this is racy, and my conclusion is that it's
> "less" racy than the original. rpm->suspended gets toggled in the middle
> of the suspend/resume sequences. So it could be halfway. Dunno if
> anything *after* those toggles depends on the state having been changed
> already; didn't find any. Maybe Imre has a better idea.
>
> Also, pm_runtime_suspended() seems more reliable when suspend/resume
> fails.
The flag was added in the initial runtime PM enabling patch to detect
MMIO accesses while runtime suspended, looks like pm_runtime_suspended()
would've worked ok already at that point.
I wondered how the above detection would change in the system suspend /
resume handlers but that looks ok as well with the disable_depth check
in pm_runtime_suspended():
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
> Acked-by: Jani Nikula <jani.nikula@xxxxxxxxx>
>
>
> >
> > Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
> > Cc: Imre Deak <imre.deak@xxxxxxxxx>
> >
> > Signed-off-by: Jouni Högander <jouni.hogander@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_display_power.c | 2 +-
> > drivers/gpu/drm/i915/i915_driver.c | 3 ---
> > drivers/gpu/drm/i915/i915_gpu_error.c | 2 +-
> > drivers/gpu/drm/i915/intel_runtime_pm.c | 1 -
> > drivers/gpu/drm/i915/intel_runtime_pm.h | 4 ++--
> > 5 files changed, 4 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
> > index 68cf5e6b0b46..889bb26009a2 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> > @@ -216,7 +216,7 @@ bool __intel_display_power_is_enabled(struct drm_i915_private *dev_priv,
> > struct i915_power_well *power_well;
> > bool is_enabled;
> >
> > - if (dev_priv->runtime_pm.suspended)
> > + if (pm_runtime_suspended(dev_priv->drm.dev))
> > return false;
> >
> > is_enabled = true;
> > diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> > index f8dbee7a5af7..cd98ee740976 100644
> > --- a/drivers/gpu/drm/i915/i915_driver.c
> > +++ b/drivers/gpu/drm/i915/i915_driver.c
> > @@ -1569,8 +1569,6 @@ static int intel_runtime_suspend(struct device *kdev)
> > if (root_pdev)
> > pci_d3cold_disable(root_pdev);
> >
> > - rpm->suspended = true;
> > -
> > /*
> > * FIXME: We really should find a document that references the arguments
> > * used below!
> > @@ -1621,7 +1619,6 @@ static int intel_runtime_resume(struct device *kdev)
> > disable_rpm_wakeref_asserts(rpm);
> >
> > intel_opregion_notify_adapter(dev_priv, PCI_D0);
> > - rpm->suspended = false;
> >
> > root_pdev = pcie_find_root_port(pdev);
> > if (root_pdev)
> > diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
> > index 4008bb09fdb5..a60bab177c55 100644
> > --- a/drivers/gpu/drm/i915/i915_gpu_error.c
> > +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
> > @@ -1972,7 +1972,7 @@ static void capture_gen(struct i915_gpu_coredump *error)
> > struct drm_i915_private *i915 = error->i915;
> >
> > error->wakelock = atomic_read(&i915->runtime_pm.wakeref_count);
> > - error->suspended = i915->runtime_pm.suspended;
> > + error->suspended = pm_runtime_suspended(i915->drm.dev);
> >
> > error->iommu = i915_vtd_active(i915);
> > error->reset_count = i915_reset_count(&i915->gpu_error);
> > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > index 6d8e5e5c0cba..8743153fad87 100644
> > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > @@ -652,7 +652,6 @@ void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm)
> >
> > rpm->kdev = kdev;
> > rpm->available = HAS_RUNTIME_PM(i915);
> > - rpm->suspended = false;
> > atomic_set(&rpm->wakeref_count, 0);
> >
> > init_intel_runtime_pm_wakeref(rpm);
> > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h b/drivers/gpu/drm/i915/intel_runtime_pm.h
> > index 764b183ae452..f79cda7a2503 100644
> > --- a/drivers/gpu/drm/i915/intel_runtime_pm.h
> > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.h
> > @@ -6,6 +6,7 @@
> > #ifndef __INTEL_RUNTIME_PM_H__
> > #define __INTEL_RUNTIME_PM_H__
> >
> > +#include <linux/pm_runtime.h>
> > #include <linux/types.h>
> >
> > #include "intel_wakeref.h"
> > @@ -43,7 +44,6 @@ struct intel_runtime_pm {
> > atomic_t wakeref_count;
> > struct device *kdev; /* points to i915->drm.dev */
> > bool available;
> > - bool suspended;
> > bool irqs_enabled;
> > bool no_wakeref_tracking;
> >
> > @@ -110,7 +110,7 @@ intel_rpm_wakelock_count(int wakeref_count)
> > static inline void
> > assert_rpm_device_not_suspended(struct intel_runtime_pm *rpm)
> > {
> > - WARN_ONCE(rpm->suspended,
> > + WARN_ONCE(pm_runtime_suspended(rpm->kdev),
> > "Device suspended during HW access\n");
> > }
>
> --
> Jani Nikula, Intel
