From: Thierry Reding <thierry.reding@gmail.com>
To: Nicolin Chen <nicoleotsuka@gmail.com>
Cc: sboyd@codeaurora.org, pdeschrijver@nvidia.com,
linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-clk@vger.kernel.org, jonathanh@nvidia.com,
mturquette@baylibre.com, pgaikwad@nvidia.com
Subject: Re: [PATCH v2] clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init
Date: Thu, 19 Oct 2017 11:44:22 +0200 [thread overview]
Message-ID: <20171019094422.GI9005@ulmo> (raw)
In-Reply-To: <20171019092919.GA7252@Asurada>
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On Thu, Oct 19, 2017 at 02:29:20AM -0700, Nicolin Chen wrote:
> On Fri, Sep 15, 2017 at 12:10:13PM -0700, Nicolin Chen wrote:
> > Below is the call trace of tegra210_init_pllu() function:
> > start_kernel()
> > -> time_init()
> > --> of_clk_init()
> > ---> tegra210_clock_init()
> > ----> tegra210_pll_init()
> > -----> tegra210_init_pllu()
> >
> > Because the preemption is disabled in the start_kernel before calling
> > time_init, tegra210_init_pllu is actually in an atomic context while
> > it includes a readl_relaxed_poll_timeout that might sleep.
> >
> > So this patch just changes this readl_relaxed_poll_timeout() to its
> > atomic version.
> >
> > Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> > Acked-By: Peter De Schrijver <pdeschrijver@nvidia.com>
>
> Thierry, can you also take a look at this one? I sent a month ago. Thanks.
I'm wondering why we're not seeing a splat for this. Usually the kernel
will warn if you sleep during atomic context. Does this mean we're just
not hitting that case? readx_poll_timeout() has a might_sleep_if(), and
therefore it should always cause the splat.
Any ideas why this has gone unnoticed for all this time?
Thierry
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next prev parent reply other threads:[~2017-10-19 9:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-15 19:10 [PATCH v2] clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init Nicolin Chen
2017-09-15 19:10 ` Nicolin Chen
[not found] ` <1505502613-11801-1-git-send-email-nicoleotsuka-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2017-10-19 9:29 ` Nicolin Chen
2017-10-19 9:29 ` Nicolin Chen
2017-10-19 9:44 ` Thierry Reding [this message]
2017-10-19 18:42 ` Nicolin Chen
2017-10-20 0:19 ` Nicolin Chen
2017-10-20 0:19 ` Nicolin Chen
2017-10-20 10:20 ` Jon Hunter
2017-10-20 10:20 ` Jon Hunter
2017-10-20 18:24 ` Nicolin Chen
2017-10-20 11:38 ` Thierry Reding
2017-10-20 11:38 ` Thierry Reding
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