Re: serial console problems with 2.4.4

[Fabrice Gautier <gautier@email.enst.fr>]

On 02 May 2001 10:37:21 -0600
ebiederm@xmission.com (Eric W. Biederman) wrote:

> Fabrice Gautier <gautier@email.enst.fr> writes:
> > So this this probably a sulogin/mingetty problem. They should set the
> > CREAD flag in your tty c_cflag.
> > 
> > the patch for busybox repalced the line
> > 	tty.c_cflag |= HUPCL|CLOCAL
> > by
> > 	tty.c_cflag |= CREAD|HUPCL|CLOCAL
> > 	
> > Hope this help.
> 
> This part is correct.  
> 
> However the kernel sets CREAD by default.  

Are your sure? Wasn't this the behaviour for 2.4.2  but changed in 2.4.3

> sysvinit (and possibly other inits) clears CREAD.

In my case I was using busybox as init. So there is no sysinit or any other
init called before this line.


> I wish I knew where the breakage actually occured.

Just look at this diff on serial.c between 2.4.2 and 2.4.3:

--- serial.c	Sat Apr 21 17:22:53 2001
+++ ../../../linux-2.4.2/drivers/char/serial.c	Sat Feb 17 01:02:36 2001
@@ -1764,8 +1765,8 @@
 	/*
 	 * !!! ignore all characters if CREAD is not set
 	 */
-//	if ((cflag & CREAD) == 0)
-//		info->ignore_status_mask |= UART_LSR_DR;
+	if ((cflag & CREAD) == 0)
+		info->ignore_status_mask |= UART_LSR_DR;
 	save_flags(flags); cli();
 	if (uart_config[info->state->type].flags & UART_STARTECH) {
 		serial_outp(info, UART_LCR, 0xBF);


-- 
Fabrice Gautier <gautier@email.enstfr>