From: Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
To: Nicolin Chen
<nicoleotsuka-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
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,
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: Fri, 20 Oct 2017 11:20:24 +0100 [thread overview]
Message-ID: <731a934a-4e78-b96d-239f-14cf83079605@nvidia.com> (raw)
In-Reply-To: <20171019184223.GA7415@Asurada-Nvidia>
On 19/10/17 19:42, 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).
I was thinking that same and so I clobbered the PLLU enable bit with
u-boot, however, then the kernel appears to hang on boot when enabling
the PLL. So although this is probably a separate issue, I am curious if
you have booted the mainline with the PLLU disabled?
Cheers
Jon
--
nvpublic
WARNING: multiple messages have this Message-ID (diff)
From: Jon Hunter <jonathanh@nvidia.com>
To: Nicolin Chen <nicoleotsuka@gmail.com>,
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>, <mturquette@baylibre.com>,
<pgaikwad@nvidia.com>
Subject: Re: [PATCH v2] clk: tegra: Use readl_relaxed_poll_timeout_atomic in tegra210_clock_init
Date: Fri, 20 Oct 2017 11:20:24 +0100 [thread overview]
Message-ID: <731a934a-4e78-b96d-239f-14cf83079605@nvidia.com> (raw)
In-Reply-To: <20171019184223.GA7415@Asurada-Nvidia>
On 19/10/17 19:42, 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).
I was thinking that same and so I clobbered the PLLU enable bit with
u-boot, however, then the kernel appears to hang on boot when enabling
the PLL. So although this is probably a separate issue, I am curious if
you have booted the mainline with the PLLU disabled?
Cheers
Jon
--
nvpublic
next prev parent reply other threads:[~2017-10-20 10:20 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
2017-10-20 0:19 ` Nicolin Chen
2017-10-20 10:20 ` Jon Hunter [this message]
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
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=731a934a-4e78-b96d-239f-14cf83079605@nvidia.com \
--to=jonathanh-ddmlm1+adcrqt0dzr+alfa@public.gmane.org \
--cc=linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=mturquette-rdvid1DuHRBWk0Htik3J/w@public.gmane.org \
--cc=nicoleotsuka-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
--cc=pdeschrijver-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org \
--cc=pgaikwad-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org \
--cc=sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org \
--cc=thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.