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Re: Carrier Detect with PPP



----- Original Message ----- 
From: "Sinclair Hansen" <sinclairh@xxxxxxx.au>
To: <dev-etrax@xxxxxxx.com>
Sent: Thursday, June 10, 2004 7:48 AM
Subject: Carrier Detect with PPP


> Sorry meant to start a new thread with this topic...
>
> I have tried with devboard82-R1_92 and linux-2.4.26, but still have the
same
> problem
>
> I noticed with the kernel xconfig that there is items for GPIO Support
that
> deal with the use of PB and PA bit mask.
>
> regards
>
> Sinclair Hansen
> R & D Engineer
> Multitrode Pty Ltd

Hi,
The ETRAX serial driver itself does not check for changes in the
status lines like it does on a PC, you can read the status from a user mode
program though.
There is a FIXME comment regarding this, but a check_modem_status()
function inspired by the one in:
drivers/char/serial.c:check_modem_status()
needs to be added for tty_hangup() to be called when CD goes low.

Calling check_modem_status() probably needs to be done from a timer
as well since we don't get an interrupt when PB pins are changed.

I will unlikely have time to implement this myself in the near future,
but at least we know it's a functionality that is missed so I will
see if I can find the resources to make it work.

Another option might be to check the CD status from a user mode
application and signal pppd from that application.

/Johan