From: Dan Carpenter <dan.carpenter@oracle.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: devel@driverdev.osuosl.org,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Pavel Machek <pavel@ucw.cz>, Len Brown <len.brown@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-pm@vger.kernel.org, kjlu@umn.edu,
linux-kernel@vger.kernel.org,
Jonathan Hunter <jonathanh@nvidia.com>,
Thierry Reding <thierry.reding@gmail.com>,
Dinghao Liu <dinghao.liu@zju.edu.cn>,
linux-tegra@vger.kernel.org,
Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org
Subject: Re: [PATCH] media: staging: tegra-vde: fix runtime pm imbalance on error
Date: Wed, 20 May 2020 18:02:30 +0300 [thread overview]
Message-ID: <20200520150230.GC30374@kadam> (raw)
In-Reply-To: <2b5d64f5-825f-c081-5d03-02655c2d9491@gmail.com>
On Wed, May 20, 2020 at 01:15:44PM +0300, Dmitry Osipenko wrote:
> 20.05.2020 12:51, Dinghao Liu пишет:
> > pm_runtime_get_sync() increments the runtime PM usage counter even
> > it returns an error code. Thus a pairing decrement is needed on
> > the error handling path to keep the counter balanced.
> >
> > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> > ---
> > drivers/staging/media/tegra-vde/vde.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/staging/media/tegra-vde/vde.c b/drivers/staging/media/tegra-vde/vde.c
> > index d3e63512a765..dd134a3a15c7 100644
> > --- a/drivers/staging/media/tegra-vde/vde.c
> > +++ b/drivers/staging/media/tegra-vde/vde.c
> > @@ -777,7 +777,7 @@ static int tegra_vde_ioctl_decode_h264(struct tegra_vde *vde,
> >
> > ret = pm_runtime_get_sync(dev);
> > if (ret < 0)
> > - goto unlock;
> > + goto put_runtime_pm;
> >
> > /*
> > * We rely on the VDE registers reset value, otherwise VDE
> >
>
> Hello Dinghao,
>
> Thank you for the patch. I sent out a similar patch a week ago [1].
>
> [1]
> https://patchwork.ozlabs.org/project/linux-tegra/patch/20200514210847.9269-2-digetx@gmail.com/
>
> The pm_runtime_put_noidle() should have the same effect as yours
> variant, although my variant won't change the last_busy RPM time, which
> I think is a bit more appropriate behavior.
I don't think either patch is correct. The right thing to do is to fix
__pm_runtime_resume() so it doesn't leak a reference count on error.
The problem is that a lot of functions don't check the return so
possibly we are relying on that behavior. We may need to introduce a
new function which cleans up properly instead of leaking reference
counts?
Also it's not documented that pm_runtime_get_sync() returns 1 sometimes
on success so it leads to a few bugs.
drivers/gpu/drm/stm/ltdc.c: ret = pm_runtime_get_sync(ddev->dev);
drivers/gpu/drm/stm/ltdc.c- if (ret) {
--
drivers/gpu/drm/stm/ltdc.c: ret = pm_runtime_get_sync(ddev->dev);
drivers/gpu/drm/stm/ltdc.c- if (ret) {
drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_pm.c: ret = pm_runtime_get_sync(pm->dev);
drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_pm.c- if (ret)
drivers/media/platform/ti-vpe/cal.c: ret = pm_runtime_get_sync(&pdev->dev);
drivers/media/platform/ti-vpe/cal.c- if (ret)
drivers/mfd/arizona-core.c: ret = pm_runtime_get_sync(arizona->dev);
drivers/mfd/arizona-core.c- if (ret != 0)
drivers/remoteproc/qcom_q6v5_adsp.c: ret = pm_runtime_get_sync(adsp->dev);
drivers/remoteproc/qcom_q6v5_adsp.c- if (ret)
drivers/spi/spi-img-spfi.c: ret = pm_runtime_get_sync(dev);
drivers/spi/spi-img-spfi.c- if (ret)
drivers/usb/dwc3/dwc3-pci.c: ret = pm_runtime_get_sync(&dwc3->dev);
drivers/usb/dwc3/dwc3-pci.c- if (ret)
drivers/watchdog/rti_wdt.c: ret = pm_runtime_get_sync(dev);
drivers/watchdog/rti_wdt.c- if (ret) {
regards,
dan carpenter
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 99c7da112c95..e280991a977d 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1082,6 +1082,9 @@ int __pm_runtime_resume(struct device *dev, int rpmflags)
retval = rpm_resume(dev, rpmflags);
spin_unlock_irqrestore(&dev->power.lock, flags);
+ if (retval < 0 && rpmflags & RPM_GET_PUT)
+ atomic_dec(&dev->power.usage_count);
+
return retval;
}
EXPORT_SYMBOL_GPL(__pm_runtime_resume);
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next prev parent reply other threads:[~2020-05-20 15:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 9:51 [PATCH] media: staging: tegra-vde: fix runtime pm imbalance on error Dinghao Liu
2020-05-20 10:15 ` Dmitry Osipenko
2020-05-20 15:02 ` Dan Carpenter [this message]
2020-05-21 3:42 ` dinghao.liu
2020-05-21 9:15 ` Dan Carpenter
2020-05-21 15:22 ` Rafael J. Wysocki
2020-05-21 17:39 ` Dan Carpenter
2020-05-22 13:10 ` Thierry Reding
2020-05-22 13:23 ` Dan Carpenter
2020-05-22 14:43 ` Thierry Reding
2020-05-28 12:08 ` Dan Carpenter
2020-05-28 12:31 ` Rafael J. Wysocki
2020-05-21 17:02 ` Rafael J. Wysocki
2020-05-20 20:15 ` kbuild test robot
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