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serial console hangs

 
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Regular Advisor

serial console hangs

hi all,

there is strange problem i m facing.
i m connecting my laptop to HA system using serial port. i m connected but After booting my HA system, my cosole not taking any input.

I am not able to operate HA system using this console. please suggest.

Thx,
MKS
9 REPLIES 9
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Honored Contributor

Re: serial console hangs

Have you configured your kernel options to use the serial console in the grub.conf file?
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
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Regular Advisor

Re: serial console hangs

#cat /proc/cmdline
console=ttyMM0,9600 ip=off root=/dev/hde2 rw

Thanks,
MKS
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Honored Contributor

Re: serial console hangs

"console=ttyMM0,9600" tells me your serial port is not the usual PC serial port (/dev/ttyS0 .. S3) but something called "Marvell MPSC". As far as I know, that is supported only on PowerPC hardware... so your "HA system" seems to be pretty special.

Can you connect to the system through the network?

If you can, please examine the output of the "cat /proc/tty/drivers" command. Does it mention "/dev/ttyMM"? If it doesn't, the driver for your serial port is not compiled into the kernel and you'll have to recompile it.

If the ttyMM device is listed in /proc/tty/drivers, you can verify the settings of the serial port with commands "setserial -g /dev/ttyMM0" and "stty -a -F /dev/ttyMM0". Check that the serial port handshaking settings match the cable you're using and the settings of your laptop.

If these settings seem correct, the next step is to check if there are processes running on the console port. Run "ps -ft console" and "ps -ft ttyMM0". If you find any processes other than (a)getty, that process might be causing the console be stuck in a mode that does not accept input. If the system is set up normally, you can use "kill -HUP " and/or "kill " commands to terminate the stuck process(es); the init process will then hopefully start a new getty on your serial console to wait for a new login.

If the getty process is not running and does not start after you've killed any other processes holding the serial console port, you should examine your /etc/inittab file: has someone removed the line that respawns the getty process for the console?

If you find something is wrong and fix it, the init process may not start the new getty process immediately. If the getty process keeps dying immediately after it restarts, init will stop respawning it for a while after a few retries. To tell the init process that the problem is (maybe) fixed and init should try again, run "telinit q". This command is also needed if you edit the /etc/inittab file.

MK
MK
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Regular Advisor

Re: serial console hangs

Hi All,

COM1 is terminating on the serial port of the computer (DB9).

Thanks,
MKS
Highlighted
Regular Advisor

Re: serial console hangs

Hi All,
#setserial -g /dev/ttyMM0
/dev/ttyMM0, UART: undefined, Port: 0x0000, IRQ: 36

#stty -a -F /dev/ttyMM0
speed 9600 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = ;
eol2 = ; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W;
lnext = ^V; flush = ^U; min = 1; time = 0;
-parenb -parodd cs8 hupcl -cstopb cread clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon
-ixoff -iuclc -ixany -imaxbel
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
-isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop
-echoprt -echoctl -echoke

Is this problem in my windows HyperTerminal setting or HA system?

I am connecting CONSOLE PORT(mini db9) on HA to 9 pin male serial port on winows baes laptop....

Plz suggest it.

Thanks,
MKS
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Honored Contributor

Re: serial console hangs

Your stty output looks good, so the port driver is probably loaded and working. The setserial output looks a bit strange, but this might be because this is not Intel x86 hardware but something else entirely... (Does a PowerPC processor even have a separate I/O address space, like the x86 processors do?)

> Is this problem in my windows HyperTerminal setting or HA system?

Impossible to say at this point; you have not told us what settings you're using with your HyperTerminal. But yes, the standard settings of "9600 8-N-1" should be OK. Or in other words, speed 9600 bps, 8 data bits, no parity, 1 stop bit. Neither RTS/CTS nor XON/XOFF handshaking seems to be enabled at the HA system side, so you should set Handshaking to None at the HyperTerminal side.

Your console is not taking any input... but did it show any output after the boot?

What does "ps -ft ttyMM0" report?
What does "grep getty /etc/inittab" report?

Please tell us the manufacturer and model of your HA system. At this point it's fairly obvious it might not be a HP product. That's all right, we won't stop helping you because of that. It's just that some PowerPC-specific forum might have more people that know the details about your hardware model.

> I am connecting CONSOLE PORT(mini db9) on HA to 9 pin male serial port on winows baes laptop....

Thanks, but without knowing the make and model of the hardware of your HA system this information does not help much.

MK
MK
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Regular Advisor

Re: serial console hangs

Hi MK,

Thanks for support.
>>Your console is not taking any input... but did it show any output after the boot?

yep, It's showing all the process starting from POST to login screen. Even we cant go into single user mode.

>>What does "ps -ft ttyMM0" report?
>>What does "grep getty /etc/inittab" report?
root@F101-SLOT-1:~# ps -ft ttyMM0
UID PID PPID C STIME TTY TIME CMD
root 7611 1 0 Dec03 ttyMM0 00:00:00 /sbin/getty console
root@F101-SLOT-1:~# grep getty /etc/inittab
# should replace it with the proper getty lines below.
con:2345:respawn:/sbin/getty console
# /sbin/getty invocations for the runlevels.
#1:2345:respawn:/sbin/getty 38400 vc/1
#2:23:respawn:/sbin/getty 38400 vc/2
#3:23:respawn:/sbin/getty 38400 vc/3
#4:23:respawn:/sbin/getty 38400 vc/4
#5:23:respawn:/sbin/getty 38400 vc/5
#6:23:respawn:/sbin/getty 38400 vc/6
#1:2345:respawn:/sbin/getty 38400 tty1
#2:23:respawn:/sbin/getty 38400 tty2
#3:23:respawn:/sbin/getty 38400 tty3
#4:23:respawn:/sbin/getty 38400 tty4
#5:23:respawn:/sbin/getty 38400 tty5
#6:23:respawn:/sbin/getty 38400 tty6
# Example how to put a getty on a serial line (for a terminal)
#T0:23:respawn:/sbin/getty -L tts/0 9600 vt100
#T0:23:respawn:/sbin/getty -L ttyS0 9600 vt100
#T1:23:respawn:/sbin/getty -L ttyS1 9600 vt100
# Example how to put a getty on a modem line.
#T3:23:respawn:/sbin/mgetty -x0 -s 57600 tts/3
#T3:23:respawn:/sbin/mgetty -x0 -s 57600 ttyS3

>>Please tell us the manufacturer and model of your HA system.
Yes it's not HP product. It's ATCA chassis (AXP 1406)having two SCXB(a.k.a. system controller) works on 2N redundency model.

Thanks,
MKS
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Honored Contributor
Solution

Re: serial console hangs

OK, now I think I have enough information to understand the general situation.

root@F101-SLOT-1:~# ps -ft ttyMM0
UID PID PPID C STIME TTY TIME CMD
root 7611 1 0 Dec03 ttyMM0 00:00:00 /sbin/getty console

The getty process *is* currently running for the console, and it has been running for quite a while (since December 3)...

root@F101-SLOT-1:~# grep getty /etc/inittab
# should replace it with the proper getty lines below.
con:2345:respawn:/sbin/getty console

...and the inittab file has a console entry, which matches the getty process listed above.

Try this:
1.) Connect the laptop and start the terminal emulator program, using the same settings you used to see the POST output

2.) While the laptop is connected, access the machine through the network and kill the getty process for the console (based on the commands listed above, the correct command would be "kill 7611").

3.) Whenever the getty process is killed, init should automatically restart it. When the getty process restarts, it will reset the serial port, clearing out possible problem situations. It will also output the text of the /etc/issue file to the serial port, so you should see it on the laptop's screen.

If this works, we have confirmed that the getty process can send data to the laptop, and the serial port parameters used by the getty process match the configuration of the laptop.

If the problem was not cleared up by the restart of the getty process, the problem would seem to be in receiving the input from the laptop.

Has the serial port of this same laptop ever been used successfully in this task before? Some laptops' serial port signal output is rather weak (to minimize battery power consumption). Some devices will ignore weak signals. You might have found a combination that does not work together.

Try with a different laptop (or with a desktop, if possible - they're more likely to have good, strong serial port signals).

Is the cable physically OK? Sharp kinks in the cable may have damaged some of the wires inside. Test the cable with another system, if possible. Also check the connectors for bent or otherwise damaged pins.

And at last, the worst case... it *is* possible that the input side of the HA system's serial port is burnt out by static electricity. If the laptop & cable can successfully be used to communicate with other similar devices, but not with *this* particular unit, then this would seem likely.

MK
MK
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Regular Advisor

Re: serial console hangs

hi MK,

thanks a lot for continuous support.

Regards,
MKS