On Wed, 16 Dec 2020 at 18:51, Lina Iyer <ilina@xxxxxxxxxxxxxx> wrote:
>
> In order to debug critical domain and device power issues, it may be
> necessary to disallow certain idle states at runtime. Let the device
> disallow a domain idle state before suspending.The domain governor shall
> check for the 'disabled' flag while determining the domain idle state.
For debug purposes, you might as well just set a dev PM Qos latency
request that corresponds to the state you want to disable. This will
then prevent the genpd governor from selecting the state.
Kind regards
Uffe
>
> Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>
> ---
> drivers/base/power/domain.c | 30 ++++++++++++++++++++++++++++
> drivers/base/power/domain_governor.c | 3 +++
> include/linux/pm_domain.h | 7 +++++++
> 3 files changed, 40 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 191539a8e06d..e4e7ab75bdea 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1926,6 +1926,36 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
> }
> EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
>
> +/**
> + * dev_pm_genpd_disable_idle_state - Disallow a PM domain's idle state
> + *
> + * @dev: device attached to the PM domain
> + * @idx: index of the PM domain's idle state to be disabled
> + * @disable: enable/disable idle state
> + *
> + * Allow a PM domain's idle state to be disabled. Disabled idle states will
> + * be ignored by the domain governor when entering idle. Devices would
> + * invoke this before calling runtime suspend.
> + */
> +int dev_pm_genpd_disable_idle_state(struct device *dev, unsigned int idx, bool disable)
> +{
> + struct generic_pm_domain *genpd;
> +
> + genpd = dev_to_genpd_safe(dev);
> + if (!genpd)
> + return -ENODEV;
> +
> + if (idx >= genpd->state_count)
> + return -EINVAL;
> +
> + genpd_lock(genpd);
> + genpd->states[idx].disabled = disable;
> + genpd_unlock(genpd);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_genpd_disable_idle_state);
> +
> static void genpd_free_default_power_state(struct genpd_power_state *states,
> unsigned int state_count)
> {
> diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c
> index 2afb7fa90d5d..8decd17c5a6a 100644
> --- a/drivers/base/power/domain_governor.c
> +++ b/drivers/base/power/domain_governor.c
> @@ -175,6 +175,9 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
> s64 min_off_time_ns;
> s64 off_on_time_ns;
>
> + if (genpd->states[state].disabled)
> + return false;
> +
> off_on_time_ns = genpd->states[state].power_off_latency_ns +
> genpd->states[state].power_on_latency_ns;
>
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index a41aea9d1c06..3d251b5b461a 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -101,6 +101,7 @@ struct genpd_power_state {
> struct fwnode_handle *fwnode;
> ktime_t idle_time;
> void *data;
> + bool disabled;
> };
>
> struct genpd_lock_ops;
> @@ -233,6 +234,7 @@ int dev_pm_genpd_add_notifier(struct device *dev, struct notifier_block *nb);
> int dev_pm_genpd_remove_notifier(struct device *dev);
> void genpd_enable_next_wakeup(struct generic_pm_domain *genpd, bool enable);
> int dev_pm_genpd_set_next_wakeup(struct device *dev, ktime_t next);
> +int dev_pm_genpd_disable_idle_state(struct device *dev, unsigned int idx, bool disable);
>
> extern struct dev_power_governor simple_qos_governor;
> extern struct dev_power_governor pm_domain_always_on_gov;
> @@ -300,6 +302,11 @@ static inline int dev_pm_genpd_set_next_wakeup(struct device *dev, ktime_t next)
> return -EOPNOTSUPP;
> }
>
> +static inline int dev_pm_genpd_disable_idle_state(struct device *dev, unsigned int idx, bool disable)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> #define simple_qos_governor (*(struct dev_power_governor *)(NULL))
> #define pm_domain_always_on_gov (*(struct dev_power_governor *)(NULL))
> #endif
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
