Re: [PATCH] PM / QoS: Fix default runtime_pm device resume latency

[Rafael J. Wysocki]

On Mon, Oct 30, 2017 at 8:10 AM, Tero Kristo <t-kristo@xxxxxx> wrote:
> The recent change to the PM QoS framework to introduce a proper
> no constraint value overlooked to handle the devices which don't
> implement PM QoS OPS. Runtime PM is one of the more severely
> impacted subsystems, failing every attempt to runtime suspend
> a device. This leads into some nasty second level issues like
> probe failures and increased power consumption among other things.

Oh, that's bad.

Sorry about breaking it and thanks for the fix!

> Fix this by adding a proper return value for devices that don't
> implement PM QoS implicitly.
>
> Fixes: 0cc2b4e5a020 ("PM / QoS: Fix device resume latency PM QoS")
> Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Applied.

> ---
>  include/linux/pm_qos.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
> index 6737a8c..d68b056 100644
> --- a/include/linux/pm_qos.h
> +++ b/include/linux/pm_qos.h
> @@ -175,7 +175,8 @@ static inline s32 dev_pm_qos_requested_flags(struct device *dev)
>  static inline s32 dev_pm_qos_raw_read_value(struct device *dev)
>  {
>         return IS_ERR_OR_NULL(dev->power.qos) ?
> -               0 : pm_qos_read_value(&dev->power.qos->resume_latency);
> +               PM_QOS_RESUME_LATENCY_NO_CONSTRAINT :
> +               pm_qos_read_value(&dev->power.qos->resume_latency);
>  }
>  #else
>  static inline enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev,
> --
> 1.9.1
>
> --
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