[RFC PATCH] mmc: tmio: properly balance RPM on remove

[RFC PATCH] mmc: tmio: properly balance RPM on remove

[Wolfram Sang]

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

Because we enabled the device with _noresume, we should disable it with
_noidle to match the ref counting of the clocks during remove().

Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

I think this is the proper fix to the problem Geert reported [1]. I am
not sure about a proper Fixes-tag, though. The corresponding _noidle
call in the probe()-error-path was added with:

aa86f1a38875 ("mmc: tmio: Fixup runtime PM management during probe")

However, from my understanding this is more fitting?

1b32999e205b ("mmc: tmio: Avoid boilerplate code in ->runtime_suspend()")

But maybe my understanding of the situation is still not perfect and
even the commit message is bogus? Ulf, since both mentioned commits are
from you, could you have a look? Thanks in advance!

   Wolfram

[1] Message-ID: <alpine.DEB.2.21.2004291630090.4052@ramsan.of.borg>

 drivers/mmc/host/tmio_mmc_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index 9520bd94cf43..9a4ae954553b 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -1235,7 +1235,7 @@ void tmio_mmc_host_remove(struct tmio_mmc_host *host)
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
 	if (host->native_hotplug)
 		pm_runtime_put_noidle(&pdev->dev);
-	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 }
 EXPORT_SYMBOL_GPL(tmio_mmc_host_remove);
-- 
2.20.1

Re: [RFC PATCH] mmc: tmio: properly balance RPM on remove

[Ulf Hansson]

On Wed, 13 May 2020 at 19:12, Wolfram Sang <wsa@kernel.org> wrote:
>
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
>
> Because we enabled the device with _noresume, we should disable it with
> _noidle to match the ref counting of the clocks during remove().
>
> Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>
> I think this is the proper fix to the problem Geert reported [1]. I am
> not sure about a proper Fixes-tag, though. The corresponding _noidle
> call in the probe()-error-path was added with:
>
> aa86f1a38875 ("mmc: tmio: Fixup runtime PM management during probe")
>
> However, from my understanding this is more fitting?
>
> 1b32999e205b ("mmc: tmio: Avoid boilerplate code in ->runtime_suspend()")
>
> But maybe my understanding of the situation is still not perfect and
> even the commit message is bogus? Ulf, since both mentioned commits are
> from you, could you have a look? Thanks in advance!

I did start to look at it, but got sidetracked with other things.
Anyway, I will check in the next couple of days.

Kind regards
Uffe

>
>    Wolfram
>
> [1] Message-ID: <alpine.DEB.2.21.2004291630090.4052@ramsan.of.borg>
>
>  drivers/mmc/host/tmio_mmc_core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
> index 9520bd94cf43..9a4ae954553b 100644
> --- a/drivers/mmc/host/tmio_mmc_core.c
> +++ b/drivers/mmc/host/tmio_mmc_core.c
> @@ -1235,7 +1235,7 @@ void tmio_mmc_host_remove(struct tmio_mmc_host *host)
>         pm_runtime_dont_use_autosuspend(&pdev->dev);
>         if (host->native_hotplug)
>                 pm_runtime_put_noidle(&pdev->dev);
> -       pm_runtime_put_sync(&pdev->dev);
> +       pm_runtime_put_noidle(&pdev->dev);
>         pm_runtime_disable(&pdev->dev);
>  }
>  EXPORT_SYMBOL_GPL(tmio_mmc_host_remove);
> --
> 2.20.1
>

Re: [RFC PATCH] mmc: tmio: properly balance RPM on remove

[Wolfram Sang]

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> I did start to look at it, but got sidetracked with other things.
> Anyway, I will check in the next couple of days.

Much appreciated, thanks!


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Re: [RFC PATCH] mmc: tmio: properly balance RPM on remove

[Geert Uytterhoeven]

Hi Wolfram,

On Wed, May 13, 2020 at 7:12 PM Wolfram Sang <wsa@kernel.org> wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
>
> Because we enabled the device with _noresume, we should disable it with
> _noidle to match the ref counting of the clocks during remove().
>
> Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

> I think this is the proper fix to the problem Geert reported [1]. I am

Thanks, I can confirm this fixes the issue on unbind, so
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

> not sure about a proper Fixes-tag, though. The corresponding _noidle
> call in the probe()-error-path was added with:
>
> aa86f1a38875 ("mmc: tmio: Fixup runtime PM management during probe")

That one also added a pm_runtime_put() call to the normal probe path,
but a pm_runtime_put_noidle() call to the error path, causing another
possible imbalance, which is still there.
So I guess the former has to be replaced by a _noidle call, too?

Also, the conditional

        if (_host->native_hotplug)
                pm_runtime_get_noresume(&pdev->dev);

in probe() is not undone in the error path.

> However, from my understanding this is more fitting?
>
> 1b32999e205b ("mmc: tmio: Avoid boilerplate code in ->runtime_suspend()")
>
> But maybe my understanding of the situation is still not perfect and
> even the commit message is bogus? Ulf, since both mentioned commits are
> from you, could you have a look? Thanks in advance!
>
>    Wolfram
>
> [1] Message-ID: <alpine.DEB.2.21.2004291630090.4052@ramsan.of.borg>

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds