serial console problems under 2.4.4/5

serial console problems under 2.4.4/5

[Narayan Desai]

Hi. I have started having serial console problems in the last bunch of
kernel releases. I have tried various 2.4.4 and 2.4.5 ac kernels (up
to and including 2.4.5-ac4) and the problem has persisted. The problem
is basically that serial console doesn't recieve. I know that the
hardware works properly, and lilo and other kernels even work fine
from serial console. As far as I can tell, only one direction is
broken, serial receive. (ie, an echo foo > /dev/ttyS0 shows up on
the serial console, but an echo to the serial device on the other end
of the console never shows up)

The serial hardware is detected:
Serial driver version 5.05b (2001-05-03) with MANY_PORTS SHARE_IRQ SERIAL_PCI enabled 
ttyS00 at 0x03f8 (irq = 4) is a 16550A 
ttyS01 at 0x02f8 (irq = 3) is a 16550A 

the pertinant parts of .config are:
CONFIG_SERIAL=y
CONFIG_SERIAL_CONSOLE=y
# CONFIG_SERIAL_EXTENDED is not set
CONFIG_SERIAL_NONSTANDARD=y
# CONFIG_COMPUTONE is not set
CONFIG_ROCKETPORT=y
# CONFIG_CYCLADES is not set

Has anyone else seen this, or have any ideas what is broken?
thanks...
 -nld

Re: serial console problems under 2.4.4/5

[Miquel van Smoorenburg]

In article <yrxofscdnpj.fsf@terra.mcs.anl.gov>,
Narayan Desai <desai@mcs.anl.gov> wrote:
>Hi. I have started having serial console problems in the last bunch of
>kernel releases. I have tried various 2.4.4 and 2.4.5 ac kernels (up
>to and including 2.4.5-ac4) and the problem has persisted. The problem
>is basically that serial console doesn't recieve.

The serial driver now pays attention to the CREAD bit. Sysvinit
clears it, so that's where it goes wrong.

I don't think this change should have gone into a 'stable' kernel
version. 2.5.0 would have been fine, not 2.4.4

Mike.

Re: serial console problems under 2.4.4/5

[Narayan Desai]

>>>>> "Mike" == Miquel van Smoorenburg <miquels@cistron-office.nl> writes:

Mike> In article <yrxofscdnpj.fsf@terra.mcs.anl.gov>,
Mike> Narayan Desai <desai@mcs.anl.gov> wrote:
>> Hi. I have started having serial console problems in the last bunch
>> of kernel releases. I have tried various 2.4.4 and 2.4.5 ac kernels
>> (up to and including 2.4.5-ac4) and the problem has persisted. The
>> problem is basically that serial console doesn't recieve.

Mike> The serial driver now pays attention to the CREAD bit. Sysvinit
Mike> clears it, so that's where it goes wrong.

Mike> I don't think this change should have gone into a 'stable'
Mike> kernel version. 2.5.0 would have been fine, not 2.4.4

How would I go about resetting this so that serial console worked
again? thanks...
 -nld

Re: serial console problems under 2.4.4/5

[Miquel van Smoorenburg]

In article <yrxsnhot1ec.fsf@terra.mcs.anl.gov>,
Narayan Desai <desai@mcs.anl.gov> wrote:
>>>>>> "Mike" == Miquel van Smoorenburg <miquels@cistron-office.nl> writes:
>
>Mike> In article <yrxofscdnpj.fsf@terra.mcs.anl.gov>,
>Mike> Narayan Desai <desai@mcs.anl.gov> wrote:
>>> Hi. I have started having serial console problems in the last bunch
>>> of kernel releases. I have tried various 2.4.4 and 2.4.5 ac kernels
>>> (up to and including 2.4.5-ac4) and the problem has persisted. The
>>> problem is basically that serial console doesn't recieve.
>
>Mike> The serial driver now pays attention to the CREAD bit. Sysvinit
>Mike> clears it, so that's where it goes wrong.
>
>Mike> I don't think this change should have gone into a 'stable'
>Mike> kernel version. 2.5.0 would have been fine, not 2.4.4

Okay it was 2.4.3 when it went in

>How would I go about resetting this so that serial console worked
>again? thanks...

Fix sysvinit. Oh and all getty programs etc - everything that
mucks around with termios.

Alternatively revert the change to drivers/char/serial.c

See also http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg42426.html

Oh *ahem* I just read the entire thread again and I remembered it
wrong. It's not the CREAD handling perse, it's something else that
has changed that caused this, but it appears that a solution
hasn't been found yet. Except for fixing all user-space programs.
Sysvinit, agetty, busybox etc etc

Okay so ignore my earlier comments. Sorry.

Mike.