linux-kernel - Re: [PATCH v6 1/5] soc: qcom: rpmh-rsc: Correctly ignore CPU_CLUSTER

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Date:   Thu, 14 May 2020 19:29:41 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Evan Green <evgreen@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Maulik Shah <mkshah@...eaurora.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 1/5] soc: qcom: rpmh-rsc: Correctly ignore
 CPU_CLUSTER_PM notifications

Hi,

On Mon, May 4, 2020 at 10:50 AM Douglas Anderson <dianders@...omium.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@...omium.org>
> Signed-off-by: Douglas Anderson <dianders@...omium.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