From: Nicolin Chen <nicoleotsuka-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org,
pdeschrijver-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org,
mturquette-rdvid1DuHRBWk0Htik3J/w@public.gmane.org,
pgaikwad-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org
Subject: Re: [PATCH v2] clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init
Date: Thu, 19 Oct 2017 17:19:01 -0700 [thread overview]
Message-ID: <20171020001859.GA9196@Asurada-Nvidia> (raw)
In-Reply-To: <20171019184223.GA7415@Asurada-Nvidia>
On Thu, Oct 19, 2017 at 11:42:24AM -0700, Nicolin Chen wrote:
> On Thu, Oct 19, 2017 at 11:44:22AM +0200, Thierry Reding 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()
>
> > 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?
>
> Yes.
>
> > readx_poll_timeout() has a might_sleep_if(), and
> > therefore it should always cause the splat.
>
> That's true as long as CONFIG_DEBUG_ATOMIC_SLEEP is enabled locally.
>
> > Any ideas why this has gone unnoticed for all this time?
>
> We can see in the tegra210_init_pllu() function that it'll not call
> tegra210_enable_pllu() if pllu is already enabled (by bootloader).
>
> You can verify it by adding an irqs_disabled() in this routine. The
> function is called during system-boot and suspend-n-resume. And both
A correction: using mainline kernel, only system-boot as the commit log
describes.
> cases should be irqs_disabled().
>
> Thanks
> Nicolin
WARNING: multiple messages have this Message-ID (diff)
From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Thierry Reding <thierry.reding@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 17:19:01 -0700 [thread overview]
Message-ID: <20171020001859.GA9196@Asurada-Nvidia> (raw)
In-Reply-To: <20171019184223.GA7415@Asurada-Nvidia>
On Thu, Oct 19, 2017 at 11:42:24AM -0700, Nicolin Chen wrote:
> On Thu, Oct 19, 2017 at 11:44:22AM +0200, Thierry Reding 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()
>
> > 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?
>
> Yes.
>
> > readx_poll_timeout() has a might_sleep_if(), and
> > therefore it should always cause the splat.
>
> That's true as long as CONFIG_DEBUG_ATOMIC_SLEEP is enabled locally.
>
> > Any ideas why this has gone unnoticed for all this time?
>
> We can see in the tegra210_init_pllu() function that it'll not call
> tegra210_enable_pllu() if pllu is already enabled (by bootloader).
>
> You can verify it by adding an irqs_disabled() in this routine. The
> function is called during system-boot and suspend-n-resume. And both
A correction: using mainline kernel, only system-boot as the commit log
describes.
> cases should be irqs_disabled().
>
> Thanks
> Nicolin
next prev parent reply other threads:[~2017-10-20 0:19 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
2017-10-19 18:42 ` Nicolin Chen
2017-10-20 0:19 ` Nicolin Chen [this message]
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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