RE: Linux-2.4.20 modem control

RE: Linux-2.4.20 modem control

[Ed Vance]

On Thu, Mar 20, 2003 at 2:14 PM, Richard B. Johnson wrote:
> 
> [SNIPPED...]
> 
> This patch works (no other promises).
> 
> --- linux-2.4.20/drivers/char/serial.c.orig	2003-03-20 
> 16:21:55.000000000 -0500
> +++ linux-2.4.20/drivers/char/serial.c	2003-03-20 
> 16:31:23.000000000 -0500
> @@ -1538,8 +1538,12 @@
>  	serial_out(info, UART_LCR, serial_inp(info, UART_LCR) & 
> ~UART_LCR_SBC);
> 
>  	if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
> -		info->MCR &= ~(UART_MCR_DTR|UART_MCR_RTS);
> -	serial_outp(info, UART_MCR, info->MCR);
> +        {
> +           serial_outp(info, UART_MCR,info->MCR & 
> ~(UART_MCR_DTR|UART_MCR_RTS));
> +           set_current_state(TASK_INTERRUPTIBLE);
> +           schedule_timeout(HZ/2);              /* 
> Disconnect modem  */
> +        }
> +	serial_outp(info, UART_MCR, info->MCR);  /* Don't keep it off */
> 
>  	/* disable FIFO's */
>  	serial_outp(info, UART_FCR, (UART_FCR_ENABLE_FIFO |
> 
Hi Richard,

I'm not sure it's a Good Thing(tm) to call schedule_timeout() with 
the interrupts disabled. The shutdown function is framed by 
save_flags();cli and restore_flags(). Don't know exactly what the 
downside of that could be. 

Is the re-enable of DTR actually necessary to get agetty to work? 
DTR is supposed to stay off until the next open. 

Still, if it works for you, it works. 

Cheers,
Ed

---------------------------------------------------------------- 
Ed Vance              edv (at) macrolink (dot) com
Macrolink, Inc.       1500 N. Kellogg Dr  Anaheim, CA  92807
----------------------------------------------------------------

RE: Linux-2.4.20 modem control

[Richard B. Johnson]

On Thu, 20 Mar 2003, Ed Vance wrote:

> On Thu, Mar 20, 2003 at 2:14 PM, Richard B. Johnson wrote:
> >
> > [SNIPPED...]
> >
> > This patch works (no other promises).
> >
> > --- linux-2.4.20/drivers/char/serial.c.orig	2003-03-20
> > 16:21:55.000000000 -0500
> > +++ linux-2.4.20/drivers/char/serial.c	2003-03-20
> > 16:31:23.000000000 -0500
> > @@ -1538,8 +1538,12 @@
> >  	serial_out(info, UART_LCR, serial_inp(info, UART_LCR) &
> > ~UART_LCR_SBC);
> >
> >  	if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
> > -		info->MCR &= ~(UART_MCR_DTR|UART_MCR_RTS);
> > -	serial_outp(info, UART_MCR, info->MCR);
> > +        {
> > +           serial_outp(info, UART_MCR,info->MCR &
> > ~(UART_MCR_DTR|UART_MCR_RTS));
> > +           set_current_state(TASK_INTERRUPTIBLE);
> > +           schedule_timeout(HZ/2);              /*
> > Disconnect modem  */
> > +        }
> > +	serial_outp(info, UART_MCR, info->MCR);  /* Don't keep it off */
> >
> >  	/* disable FIFO's */
> >  	serial_outp(info, UART_FCR, (UART_FCR_ENABLE_FIFO |
> >
> Hi Richard,
>
> I'm not sure it's a Good Thing(tm) to call schedule_timeout() with
> the interrupts disabled. The shutdown function is framed by
> save_flags();cli and restore_flags(). Don't know exactly what the
> downside of that could be.
>
> Is the re-enable of DTR actually necessary to get agetty to work?
> DTR is supposed to stay off until the next open.
>
> Still, if it works for you, it works.
>
> Cheers,
> Ed

Yes. DTR must be high or the modem will never answer an incoming call.
The `getty` waits in a blocking open until the carrier is detected.
The carrier will never be detected if DTR is low. After the hangup
occurs, you need to restore the modem settings.


Cheers,
Dick Johnson
Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.

Winbond 83697hf support?

[Kirk Reiser]

Hi Folks:  I was wondering if anyone knew of any driver support for
the system monitoring functions of the Winbond w83697hf or any of that
family of support chips.

I have done searches on google and through the 2.4.20 source code but
can only find reference to the chip as an identifier in the parport_pc.c
file.  Google finds nothing accept as a component on many mother
boards.

Any pointers would be appreciated.
  Kirk

-- 

Kirk Reiser				The Computer Braille Facility
e-mail: kirk@braille.uwo.ca		University of Western Ontario
phone: (519) 661-3061