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

From: Greg Kroah-Hartman
Date: Sat Mar 05 2016 - 17:27:28 EST


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
> ïïïï+HHïï0.699378] 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@xxxxxxxxxx>
> ---
> 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