Re: [Intel-gfx] [PATCH v2 38/39] drm/i915: add descriptions for some RPM macros at intel_gt_pm.h

[Mauro Carvalho Chehab <mauro.chehab@linux.intel.com>]

On Tue, 9 Aug 2022 06:12:06 -0400
Rodrigo Vivi <rodrigo.vivi@intel.com> wrote:

> On Wed, Jul 13, 2022 at 09:12:26AM +0100, Mauro Carvalho Chehab wrote:
> > The intel_gt_pm.h file contains some convenient macros to be used
> > in GT code in order to get/put runtime PM references and for
> > checking them.
> > 
> > Add descriptions based on the ones at intel_wakeref.h and
> > intel_runtime_pm.c.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
> > ---
> > 
> > To avoid mailbombing on a large number of people, only mailing lists were C/C on the cover.
> > See [PATCH v2 00/39] at: https://lore.kernel.org/all/cover.1657699522.git.mchehab@kernel.org/
> > 
> >  Documentation/gpu/i915.rst            |  2 +
> >  drivers/gpu/drm/i915/gt/intel_gt_pm.h | 62 +++++++++++++++++++++++++++
> >  2 files changed, 64 insertions(+)
> > 
> > diff --git a/Documentation/gpu/i915.rst b/Documentation/gpu/i915.rst
> > index 6bb50edc6d79..9862d504df4d 100644
> > --- a/Documentation/gpu/i915.rst
> > +++ b/Documentation/gpu/i915.rst
> > @@ -709,6 +709,8 @@ Table Manager (TTM)
> >  
> >  .. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
> >  
> > +.. kernel-doc:: drivers/gpu/drm/i915/gt/intel_gt_pm.h  
> 
> I don't believe this is the right placement for this.

I'll add it then at:

	Other GT functionality

Section.

Regards,
Mauro


> 
> the rest lgtm
> 
> > +
> >  Graphics Execution Manager (GEM)
> >  --------------------------------
> >  
> > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> > index bc898df7a48c..a8ea6846980a 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> > @@ -11,21 +11,57 @@
> >  #include "intel_gt_types.h"
> >  #include "intel_wakeref.h"
> >  
> > +/**
> > + * intel_gt_pm_is_awake: Query whether the runtime PM is awake held
> > + *
> > + * @gt: pointer to the graphics engine
> > + *
> > + * Returns: true if a runtime pm reference is currently held and the GT is
> > + * awake.
> > + */
> >  static inline bool intel_gt_pm_is_awake(const struct intel_gt *gt)
> >  {
> >  	return intel_wakeref_is_active(&gt->wakeref);
> >  }
> >  
> > +/**
> > + * intel_gt_pm_get: grab a runtime PM reference ensuring that GT is powered up
> > + * @gt: pointer to the graphics engine
> > + *
> > + * Any runtime pm reference obtained by this function must have a symmetric
> > + * call to intel_gt_pm_put() to release the reference again.
> > + *
> > + * Note that this is allowed to fail, in which case the runtime-pm wakeref
> > + * will be released and the acquisition unwound.
> > + */
> >  static inline void intel_gt_pm_get(struct intel_gt *gt)
> >  {
> >  	intel_wakeref_get(&gt->wakeref);
> >  }
> >  
> > +/**
> > + * __intel_gt_pm_get: Acquire the runtime PM reference again
> > + * @gt: pointer to the graphics engine which contains the wakeref
> > + *
> > + * Increment the PM reference counter, only valid if it is already held by
> > + * the caller.
> > + *
> > + * See intel_gt_pm_get().
> > + */
> >  static inline void __intel_gt_pm_get(struct intel_gt *gt)
> >  {
> >  	__intel_wakeref_get(&gt->wakeref);
> >  }
> >  
> > +/**
> > + * intel_gt_pm_get_if_awake: Acquire the runtime PM reference if active
> > + * @gt: pointer to the graphics engine which contains the PM reference
> > + *
> > + * Acquire a hold on the PM reference, but only if the GT is already
> > + * active.
> > + *
> > + * Returns: true if the wakeref was acquired, false otherwise.
> > + */
> >  static inline bool intel_gt_pm_get_if_awake(struct intel_gt *gt)
> >  {
> >  	return intel_wakeref_get_if_active(&gt->wakeref);
> > @@ -36,6 +72,14 @@ static inline void intel_gt_pm_might_get(struct intel_gt *gt)
> >  	intel_wakeref_might_get(&gt->wakeref);
> >  }
> >  
> > +/**
> > + * intel_gt_pm_put: Release the runtime PM reference
> > + * @gt: pointer to the graphics engine which contains the PM reference
> > + *
> > + * Release our hold on the runtime PM for GT.
> > + *
> > + * It might power down the GT right away if this is the last reference.
> > + */
> >  static inline void intel_gt_pm_put(struct intel_gt *gt)
> >  {
> >  	intel_wakeref_put(&gt->wakeref);
> > @@ -51,10 +95,28 @@ static inline void intel_gt_pm_might_put(struct intel_gt *gt)
> >  	intel_wakeref_might_put(&gt->wakeref);
> >  }
> >  
> > +/**
> > + * with_intel_gt_pm - get a GT reference ensuring that GT is powered up,
> > + *	run some code and then put the reference away.
> > + *
> > + * @gt: pointer to the gt
> > + * @tmp: pointer to a temporary wakeref.
> > + */
> >  #define with_intel_gt_pm(gt, tmp) \
> >  	for (tmp = 1, intel_gt_pm_get(gt); tmp; \
> >  	     intel_gt_pm_put(gt), tmp = 0)
> >  
> > +/**
> > + * intel_gt_pm_wait_for_idle: Wait until the runtime PM reference is idle
> > + * @gt: pointer to the graphics engine which contains the PM reference
> > + *
> > + * Wait for the earlier asynchronous release of the runtime PM reference. Note
> > + * this will wait for any third party as well, so make sure you only wait
> > + * when you have control over the GT runtime PM and trust no one else is
> > + * acquiring it.
> > + *
> > + * Return: 0 on success, error code if killed.
> > + */
> >  static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt)
> >  {
> >  	return intel_wakeref_wait_for_idle(&gt->wakeref);
> > -- 
> > 2.36.1
> >