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SubjectRe: Re: [PATCH] spi: tegra20-slink: Fix runtime PM imbalance on error
On Fri, May 22, 2020 at 6:20 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Fri, May 22, 2020 at 10:46 AM <dinghao.liu@zju.edu.cn> wrote:

...

> Moreover, consider below case
>
> CPU1: ...somewhere in the code...
> pm_runtime_get() // with success!
> ...see below...
> pm_runtime_put()
>
> CPU2: ...on parallel thread...
> ret = pm_runtime_get_sync() // failed!
> if (ret)
> pm_runtime_put() // oi vei, we put device into sleep
>
> So, there is a potential issue.

...and even if it's impossible (no bugs in runtime PM core, etc) the
code with put() looks suspicious.

--
With Best Regards,
Andy Shevchenko

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