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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Andy Gross <andy.gross@linaro.org>,
	Stephen Boyd <sboyd@codeaurora.org>,
	David Brown <david.brown@linaro.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: Sat, 5 Mar 2016 14:26:59 -0800	[thread overview]
Message-ID: <20160305222659.GA6557@kroah.com> (raw)
In-Reply-To: <1456831373-14839-1-git-send-email-srinivas.kandagatla@linaro.org>

On Tue, Mar 01, 2016 at 11:22:53AM +0000, 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.
> 
> 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>
> ---
>  drivers/tty/serial/msm_serial.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
> index dcde955..0a31b3e 100644
> --- a/drivers/tty/serial/msm_serial.c
> +++ b/drivers/tty/serial/msm_serial.c
> @@ -1580,7 +1580,6 @@ static int msm_serial_probe(struct platform_device *pdev)
>  		if (IS_ERR(msm_port->pclk))
>  			return PTR_ERR(msm_port->pclk);
>  
> -		clk_set_rate(msm_port->clk, 1843200);

Delete the unneeded blank line as well please, when you resend this.

thanks,

greg k-h

      parent reply	other threads:[~2016-03-05 22:27 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
2016-03-05 22:26 ` Greg Kroah-Hartman [this message]

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