Re: wrong number of serial port detected

From: Jason Dravet
Date: Fri Dec 09 2005 - 09:36:28 EST


From: Russell King <rmk+lkml@xxxxxxxxxxxxxxxx>
To: Jason Dravet <dravet@xxxxxxxxxxx>
CC: linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: wrong number of serial port detected
Date: Thu, 8 Dec 2005 10:54:26 +0000

On Wed, Dec 07, 2005 at 09:02:03PM -0600, Jason Dravet wrote:
> >As for your 64 VT tty device nodes - these "devices" are created
> >dynamically when the device node is opened. The act of opening the
> >device node is defined to be the creation event. If the device node
> >did not exist, there would be no way to create _any_ virtual terminals.
>
> I thought there were only 7 tty devices (Ctrl-F1 to Ctrl-F7) for local
> system login? Ctrl-F7 being for Xwindows. Did I miss something?

If you look in the "init" configuration file, /etc/inittab, you'll
see lines similar to these:

The /etc/inittab file is where I got the number 7 from (6 tty plus 1 Xwindows). I have to change the inittab everytime I install FC since they switched to graphical boot (FC does not like my monitor). Let me see if I got this right: Is the reason 64 tty devices exist similiar to the reason you gave me about the 32 serial ports? You create all the nodes so they can be used at anytime. If there were only the 6 tty nodes created then if you want to direct your logger to tty12, you would first have to create that node and then tty12 could be used. If this is true how are the other 52 tty devices accessed? I don't have a F13 or F44 keys on my keyboard.

I like the idea of the patch that Dave Jones created. The question I have is with all of this plug and play stuff in our PCs shouldn't it be possible to get the correct number of ports, ask the bios or the pci bus or something?

Thanks,
Jason


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