Messages in this thread | | | Date | Fri, 13 Sep 2013 23:12:41 +0400 | From | Sergei Shtylyov <> | Subject | Re: [PATCH 2/3] USB : serial : invoke dcd_change ldisc's handler. |
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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
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