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request for serial console support
http://forums.linhes.org/viewtopic.php?f=5&t=18104		 Page 1 of 1
Author:  garlick [ Sat Mar 29, 2008 10:32 am ]
Post subject:  request for serial console support
Hi,

I'd like to run my knoppmyth based backend with a serial console, but the kernel isn't configured with static serial modules so there's no way to get /dev/console output or early kernel boot messages over serial. Maybe there is a good reason for this, but I'll ask anyway: could serial console support be enabled in some future version of knoppmyth?

The main advantage is monitor/keyboard/graphics card can go away and consume less space and power.

Thanks,

Jim
Author:  Liv2Cod [ Sat Mar 29, 2008 2:27 pm ]
Post subject: 
I think it's a good idea, too. Anything that lessens the footprint of the backend server is great. I wonder about the boot-up phase, tho.

Do some motherboards allow you to do ROM BIOS setup via console? That would be a huge benefit for my frontend. It's in an entertainment center hooked to a projection TV. The TV doesn't multi-sync well and I can't use it for maintenance because the display won't sync to 640x480. (My current process is to disconnect it, dig it out of the entertainment center, and take it upstairs for maintenance.)
Author:  cecil [ Sat Mar 29, 2008 5:58 pm ]
Post subject: 
Good idea, however you aren't providing the details I require for a feature request. Less I get the details needed, this is being piped to /dev/null.
Author:  garlick [ Sat Mar 29, 2008 6:38 pm ]
Post subject: 
Hi,

I think the main thing that's needed here is to change the kernel config to include

CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y

Then the end user can edit lilo.conf to get console working as described in various serial console FAQ's.

Regarding POST: some server class moboards support "console redirection" to com1 or com2. If yours doesn't (mine doesn't), then I guess you need a monitor/kbd around in storage to pull out for the infrequent events of reconfiguring the BIOS, debugging POST failure, and installing knoppmyth. Maybe the latter could be made to work, I don't know.

Jim
Author:  Greg Frost [ Sat Mar 29, 2008 8:04 pm ]
Post subject: 
My question would be: If you configure a serial console that way, will it prevent IR Blasters from working on that serial port. I think there would be more people wanting to use IR blasters for their Knoppmyth boxes than serial consoles.
Author:  garlick [ Sat Mar 29, 2008 8:46 pm ]
Post subject: 
The 8250 module would be initialized at boot and modprobe.conf could not pass options to it. Other than that, you have to pass a kernel command line option in order to get the kernel to actually use one of the ports as the console. Does that cause problems for irblaster people? I would think not but I'm not an irblaster user myself.
Author:  cliffsjunk [ Sun Mar 30, 2008 1:20 pm ]
Post subject: 
If I am not mistaken you could add the modules to the init ramdisk and force load them in the root and get about the same effect as compiling them in.

I don't know how to do this, but I remember someone doing this to get vesafb loaded in some distro. I use KM and Ubuntu.

Cliff
Author:  cecil [ Sun Mar 30, 2008 2:08 pm ]
Post subject: 
Greg Frost wrote:
My question would be: If you configure a serial console that way, will it prevent IR Blasters from working on that serial port. I think there would be more people wanting to use IR blasters for their Knoppmyth boxes than serial consoles.
What he said.
Author:  alien [ Mon Mar 31, 2008 1:57 am ]
Post subject: 
What about something like http://www.realweasel.com/

This would also give you access to the BIOS.

The down side is that it costs more than a graphic card.
Author:  mjl [ Mon Apr 07, 2008 6:31 pm ]
Post subject: 
Hi

Got me curious as I use to use the serial console a lot a while back :) A quick search in google "linux serial console" quickly stired up memories. I have not tried from the boot since Slakware was a pup but you can throw a tag into the append I belive to see the boot stuff.

I did an apt-get install mgetty,

added to intttab:

co:2345:respawn:/sbin/mgetty ttyS1

set up: nano -w /etc/mgetty/mgetty.config

init q

and tapping return a couple of times on my terminal brought up the login prompt.

Is that what you were seaking? If so maybe Cecil has room to stick it in the future iso?
Mike
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