Re: [PATCH 1/2] PM / Domains: Add GENPD_FLAG_SUSPEND_ON flag

[Sibi Sankar]

Kevin,
Thanks for taking time to review the
series!

On 2020-08-12 05:49, Kevin Hilman wrote:
> Sibi Sankar <sibis@xxxxxxxxxxxxxx> writes:
>
> > This is for power domains which needs to stay powered on for suspend
> > but can be powered on/off as part of runtime PM. This flag is aimed at
> > power domains coupled to remote processors which enter suspend states
> > independent to that of the application processor. Such power domains
> > are turned off only on remote processor crash/shutdown.
> >
> > Signed-off-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
>
> Seems like a useful use-case, but i think there should be a bit more
> description/documentation about what is the expected/desired behavior
> during system suspsend when a power-domain with this flag is already
> runtime-PM suspended.  Similarily, on system resume, what is the
> expected/desired behavior?

SUSPEND_ON flag is only aimed at
keeping power domains powered on
across suspend (only if its already
powered on). Also if the power domain
is runtime-PM suspended we wouldn't
want to power it on during resume.

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 0a5afca250d03..547c091618008 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1003,7 +1003,7 @@ static void genpd_sync_power_on(struct 
generic_pm_domain *genpd, bool use_lock,
 {
        struct gpd_link *link;

-       if (genpd_status_on(genpd))
+       if (genpd_status_on(genpd) || genpd_is_suspend_on(genpd))
                return;

I'll add the ^^ diff in the next
re-spin to prevent power on of
a runtime-PM suspended power
domain.

> Kevin

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