diff mbox series

[v6,1/5] soc: qcom: rpmh-rsc: Correctly ignore CPU_CLUSTER_PM notifications

Message ID 20200504104917.v6.1.Ic7096b3b9b7828cdd41cd5469a6dee5eb6abf549@changeid
State Superseded
Headers show
Series [v6,1/5] soc: qcom: rpmh-rsc: Correctly ignore CPU_CLUSTER_PM notifications | expand

Commit Message

Doug Anderson May 4, 2020, 5:50 p.m. UTC
Our switch statement doesn't have entries for CPU_CLUSTER_PM_ENTER,
CPU_CLUSTER_PM_ENTER_FAILED, and CPU_CLUSTER_PM_EXIT and doesn't have
a default.  This means that we'll try to do a flush in those cases but
we won't necessarily be the last CPU down.  That's not so ideal since
our (lack of) locking assumes we're on the last CPU.

Luckily this isn't as big a problem as you'd think since (at least on
the SoC I tested) we don't get these notifications except on full
system suspend.  ...and on full system suspend we get them on the last
CPU down.  That means that the worst problem we hit is flushing twice.
Still, it's good to make it correct.

Fixes: 985427f997b6 ("soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches")
Reported-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v6:
- Release the lock on cluster notifications.

Changes in v5:
- Corrently => Correctly

Changes in v4:
- ("...Corrently ignore CPU_CLUSTER_PM notifications") split out for v4.

Changes in v3: None
Changes in v2: None

 drivers/soc/qcom/rpmh-rsc.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Stephen Boyd May 5, 2020, 6:31 a.m. UTC | #1
Quoting Douglas Anderson (2020-05-04 10:50:15)
> Our switch statement doesn't have entries for CPU_CLUSTER_PM_ENTER,
> CPU_CLUSTER_PM_ENTER_FAILED, and CPU_CLUSTER_PM_EXIT and doesn't have
> a default.  This means that we'll try to do a flush in those cases but
> we won't necessarily be the last CPU down.  That's not so ideal since
> our (lack of) locking assumes we're on the last CPU.
> 
> Luckily this isn't as big a problem as you'd think since (at least on
> the SoC I tested) we don't get these notifications except on full
> system suspend.  ...and on full system suspend we get them on the last
> CPU down.  That means that the worst problem we hit is flushing twice.
> Still, it's good to make it correct.
> 
> Fixes: 985427f997b6 ("soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches")
> Reported-by: Stephen Boyd <swboyd@chromium.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Doug Anderson May 15, 2020, 2:29 a.m. UTC | #2
Hi,

On Mon, May 4, 2020 at 10:50 AM Douglas Anderson <dianders@chromium.org> wrote:
>
> Our switch statement doesn't have entries for CPU_CLUSTER_PM_ENTER,
> CPU_CLUSTER_PM_ENTER_FAILED, and CPU_CLUSTER_PM_EXIT and doesn't have
> a default.  This means that we'll try to do a flush in those cases but
> we won't necessarily be the last CPU down.  That's not so ideal since
> our (lack of) locking assumes we're on the last CPU.
>
> Luckily this isn't as big a problem as you'd think since (at least on
> the SoC I tested) we don't get these notifications except on full
> system suspend.  ...and on full system suspend we get them on the last
> CPU down.  That means that the worst problem we hit is flushing twice.
> Still, it's good to make it correct.
>
> Fixes: 985427f997b6 ("soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches")
> Reported-by: Stephen Boyd <swboyd@chromium.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
>
> Changes in v6:
> - Release the lock on cluster notifications.
>
> Changes in v5:
> - Corrently => Correctly
>
> Changes in v4:
> - ("...Corrently ignore CPU_CLUSTER_PM notifications") split out for v4.
>
> Changes in v3: None
> Changes in v2: None
>
>  drivers/soc/qcom/rpmh-rsc.c | 3 +++
>  1 file changed, 3 insertions(+)

The bugfixes in this series seem somewhat important to land.  Is there
something delaying them?  Are we waiting for some tags from Maulik?

-Doug
diff mbox series

Patch

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index a9e15699f55f..8c338335fc21 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -806,6 +806,9 @@  static int rpmh_rsc_cpu_pm_callback(struct notifier_block *nfb,
 	case CPU_PM_EXIT:
 		cpumask_clear_cpu(smp_processor_id(), &drv->cpus_entered_pm);
 		goto exit;
+	default:
+		ret = NOTIFY_DONE;
+		goto exit;
 	}
 
 	ret = rpmh_rsc_ctrlr_is_busy(drv);