lkml.org 
[lkml]   [2013]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/3] USB : serial : invoke dcd_change ldisc's handler.
Hello.

On 09/13/2013 07:35 PM, Paul Chavent wrote:

> Signed-off-by: Paul Chavent <paul.chavent@onera.fr>
> ---
> Documentation/pps/pps.txt | 15 +++++++++++++++
> drivers/usb/serial/generic.c | 9 +++++++++
> 2 files changed, 24 insertions(+)

> diff --git a/Documentation/pps/pps.txt b/Documentation/pps/pps.txt
> index d35dcdd..67b9a94 100644
> --- a/Documentation/pps/pps.txt
> +++ b/Documentation/pps/pps.txt
> @@ -66,6 +66,21 @@ In LinuxPPS the PPS sources are simply char devices usually mapped
> into files /dev/pps0, /dev/pps1, etc..
>
>
> +PPS with USB to serial devices
> +------------------------------
> +
> +It is possible to grab the PPS from an USB to serial device. However,
> +you should take into account the latencies and jitter introduced by
> +the USB stack. Users has reported clock instability around +-1ms when
> +synchronized with PPS through USB. This isn't suited for time server
> +synchronisation.

Thunderbird spellchecker underlines this word -- "synchronization" is
probably better.

[...]
> diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
> index 1f31e6b..877d6e0 100644
> --- a/drivers/usb/serial/generic.c
> +++ b/drivers/usb/serial/generic.c
> @@ -568,6 +568,15 @@ void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
> {
> struct tty_port *port = &usb_port->port;
>
> + if (tty) {
> + struct tty_ldisc *ld = tty_ldisc_ref(tty);

Insert an empty line after declaration as above -- keep the style
consistent, please.

> + if (ld) {
> + if (ld->ops->dcd_change)
> + ld->ops->dcd_change(tty, status);
> + tty_ldisc_deref(ld);
> + }
> + }
> +

WBR, Sergei



\
 
 \ /
  Last update: 2013-09-13 21:41    [W:0.092 / U:0.616 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site