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SubjectRe: [PATCH 58/78] media: exynos-gsc: use pm_runtime_resume_and_get()
Em Tue, 27 Apr 2021 10:18:12 +0200
Sylwester Nawrocki <s.nawrocki@samsung.com> escreveu:

> On 24.04.2021 08:45, Mauro Carvalho Chehab wrote:
> > Commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > added pm_runtime_resume_and_get() in order to automatically handle
> > dev->power.usage_count decrement on errors.
> >
> > Use the new API, in order to cleanup the error check logic.
> >
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> > ---
> > drivers/media/platform/exynos-gsc/gsc-core.c | 3 +--
> > drivers/media/platform/exynos-gsc/gsc-m2m.c | 2 +-
> > 2 files changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/platform/exynos-gsc/gsc-core.c b/drivers/media/platform/exynos-gsc/gsc-core.c
> > index 9f41c2e7097a..9d5841194f6b 100644
> > --- a/drivers/media/platform/exynos-gsc/gsc-core.c
> > +++ b/drivers/media/platform/exynos-gsc/gsc-core.c
> > @@ -1210,7 +1210,7 @@ static int gsc_remove(struct platform_device *pdev)
> > struct gsc_dev *gsc = platform_get_drvdata(pdev);
> > int i;
> >
> > - pm_runtime_get_sync(&pdev->dev);
> > + pm_runtime_resume_and_get(&pdev->dev);
> >
> > gsc_unregister_m2m_device(gsc);
> > v4l2_device_unregister(&gsc->v4l2_dev);
> > @@ -1219,7 +1219,6 @@ static int gsc_remove(struct platform_device *pdev)
> > for (i = 0; i < gsc->num_clocks; i++)
> > clk_disable_unprepare(gsc->clock[i]);
> >
> > - pm_runtime_put_noidle(&pdev->dev);
>
> If we do this then the device usage count will not get decremented
> after the pm_runtime_resume_and_get() call above and after driver
> unload/load cycle it will not be possible to suspend the device.
> I wouldn't be changing anything in gsc_remove(), pm_runtime_get_sync()
> works better in that case.

Good point.

Actually, I don't see any reason why to call a PM resume
function - either being pm_runtime_get_sync() or
pm_runtime_resume_and_get().

The code there could simply be:

static int gsc_remove(struct platform_device *pdev)
{
struct gsc_dev *gsc = platform_get_drvdata(pdev);
int i;

gsc_unregister_m2m_device(gsc);
v4l2_device_unregister(&gsc->v4l2_dev);

vb2_dma_contig_clear_max_seg_size(&pdev->dev);
for (i = 0; i < gsc->num_clocks; i++)
clk_disable_unprepare(gsc->clock[i]);

pm_runtime_disable(&pdev->dev);

dev_dbg(&pdev->dev, "%s driver unloaded\n", pdev->name);
return 0;
}

Eventually also adding:
pm_runtime_suspended(&pdev->dev);

just after pm_runtime_disable().

Regards,
Mauro

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