Re: [PATCH] tty: msm_serial: remove static clk rate setting in probe

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] tty: msm_serial: remove static clk rate setting in probe
Date	2016-03-05 23:30 +0100
Message-ID	<r9sRY-4hK-3@gated-at.bofh.it> (permalink)
References	<r7QF3-8t4-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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

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Re: [PATCH] tty: msm_serial: remove static clk rate setting in probe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-05 23:30 +0100

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