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

Rodrigo Vivi
2022-08-09T10:12:43Z

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.

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
>