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 11:42:24 -0700 [thread overview]
Message-ID: <20171019184223.GA7415@Asurada-Nvidia> (raw)
In-Reply-To: <20171019094422.GI9005@ulmo>
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
cases should be irqs_disabled().
Thanks
Nicolin
next prev parent reply other threads:[~2017-10-19 18:42 UTC|newest]
Thread overview: 8+ 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
2017-10-19 9:29 ` Nicolin Chen
2017-10-19 9:44 ` Thierry Reding
2017-10-19 18:42 ` Nicolin Chen [this message]
2017-10-20 0:19 ` Nicolin Chen
2017-10-20 10:20 ` Jon Hunter
2017-10-20 18:24 ` Nicolin Chen
2017-10-20 11:38 ` Thierry Reding
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171019184223.GA7415@Asurada-Nvidia \
--to=nicoleotsuka@gmail.com \
--cc=jonathanh@nvidia.com \
--cc=linux-clk@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=mturquette@baylibre.com \
--cc=pdeschrijver@nvidia.com \
--cc=pgaikwad@nvidia.com \
--cc=sboyd@codeaurora.org \
--cc=thierry.reding@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).