Re: serial console problems with 2.4.4

From: Fabrice Gautier (gautier@email.enst.fr)
Date: Wed May 02 2001 - 13:52:36 EST

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>

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This archive was generated by hypermail 2b29 : Mon May 07 2001 - 21:00:14 EST