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From: Stephen Boyd <sboyd@codeaurora.org>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Andy Gross <andy.gross@linaro.org>,
	David Brown <david.brown@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>,
	linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tty: msm_serial: remove static clk rate setting in probe
Date: Wed, 2 Mar 2016 17:41:10 -0800	[thread overview]
Message-ID: <20160303014110.GH24999@codeaurora.org> (raw)
In-Reply-To: <1456831373-14839-1-git-send-email-srinivas.kandagatla@linaro.org>

On 03/01, Srinivas Kandagatla wrote:
> The issue with setting up a fixed clock rate at probe is that it would
> overwrite the console rate set by the bootloader for its console device.
> This would result in serial out corruption or missing log when we system
> is booted with earlycon. This is not a issue if we boot system without
> earlycon.
> 
> This setup is ateast not required with the mainline driver.

at least? May be worth mentioning that this code used to be
required because the clk_enable() call would fail if
clk_set_rate() wasn't called first.

> 
> Originally the issue was noticed on DB410c which is based on APQ8016
> chipset.
> 
> Without this patch the console log with earlycon would look like:
> ...
> [    0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=1
> [    0.000000] NR_IRQS:64 nr_irqs:64 0
> ����+HH��0.699378] console [ttyMSM0] enabled
> [    0.699378] console [ttyMSM0] enabled
> [    0.702003] bootconsole [uart0] disabled
> [    0.702003] bootconsole [uart0] disabled
> ...
> 
> with this patch I can see all the skipped lines on the console
> 
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

otherwise

Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

  reply	other threads:[~2016-03-03  1:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-01 11:22 [PATCH] tty: msm_serial: remove static clk rate setting in probe Srinivas Kandagatla
2016-03-03  1:41 ` Stephen Boyd [this message]
2016-03-05 22:26 ` Greg Kroah-Hartman

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