From: Kevin Hilman <khilman@kernel.org>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: arm@kernel.org, agross@codeaurora.org, galak@codeaurora.org,
linux-arm-kernel@lists.infradead.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] soc: qcom: do not disable the iface clock in probe
Date: Wed, 24 Sep 2014 08:22:58 -0700 [thread overview]
Message-ID: <7hbnq5m4a5.fsf@deeprootsystems.com> (raw)
In-Reply-To: <1411500054-13600-1-git-send-email-srinivas.kandagatla@linaro.org> (Srinivas Kandagatla's message of "Tue, 23 Sep 2014 20:20:54 +0100")
Srinivas Kandagatla <srinivas.kandagatla@linaro.org> writes:
> since commit 31964ffebbb9 ("tty: serial: msm: Remove direct access to GSBI")'
> serial hangs if earlyprintk are enabled.
>
> This hang is noticed only when the GSBI driver is probed and all the
> earlyprintks before gsbi probe are seen on the console.
> The reason why it hangs is because GSBI driver disables hclk in its
> probe function without realizing that the serial IP might be in use by
> a bootconsole. As gsbi driver disables the clock in probe the
> bootconsole locks up.
> Turning off hclk's could be dangerous if there are system components
> like earlyprintk using the hclk.
This seems rather fragile. Isn't the right fix for these other
components to use the clk api to ensure the clock does not get enabled?
Kevin
WARNING: multiple messages have this Message-ID (diff)
From: khilman@kernel.org (Kevin Hilman)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] soc: qcom: do not disable the iface clock in probe
Date: Wed, 24 Sep 2014 08:22:58 -0700 [thread overview]
Message-ID: <7hbnq5m4a5.fsf@deeprootsystems.com> (raw)
In-Reply-To: <1411500054-13600-1-git-send-email-srinivas.kandagatla@linaro.org> (Srinivas Kandagatla's message of "Tue, 23 Sep 2014 20:20:54 +0100")
Srinivas Kandagatla <srinivas.kandagatla@linaro.org> writes:
> since commit 31964ffebbb9 ("tty: serial: msm: Remove direct access to GSBI")'
> serial hangs if earlyprintk are enabled.
>
> This hang is noticed only when the GSBI driver is probed and all the
> earlyprintks before gsbi probe are seen on the console.
> The reason why it hangs is because GSBI driver disables hclk in its
> probe function without realizing that the serial IP might be in use by
> a bootconsole. As gsbi driver disables the clock in probe the
> bootconsole locks up.
> Turning off hclk's could be dangerous if there are system components
> like earlyprintk using the hclk.
This seems rather fragile. Isn't the right fix for these other
components to use the clk api to ensure the clock does not get enabled?
Kevin
next prev parent reply other threads:[~2014-09-24 15:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-23 19:20 [PATCH v2] soc: qcom: do not disable the iface clock in probe Srinivas Kandagatla
2014-09-23 19:20 ` Srinivas Kandagatla
2014-09-24 4:39 ` Olof Johansson
2014-09-24 4:39 ` Olof Johansson
2014-09-24 15:22 ` Kevin Hilman [this message]
2014-09-24 15:22 ` Kevin Hilman
2014-09-24 15:30 ` Srinivas Kandagatla
2014-09-24 15:30 ` Srinivas Kandagatla
2014-09-25 22:59 ` Kevin Hilman
2014-09-25 22:59 ` Kevin Hilman
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=7hbnq5m4a5.fsf@deeprootsystems.com \
--to=khilman@kernel.org \
--cc=agross@codeaurora.org \
--cc=arm@kernel.org \
--cc=galak@codeaurora.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=srinivas.kandagatla@linaro.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.