Bizarre serial console redirection behavior with PE1950/2950 III BMC

[Alexander Dupuy]

Having set up serial console redirection and used IPMI SOL to access 
this with a number of PE1950 systems last year, I thought I understood 
it pretty well.  However, having recently received some newer PE1950 III 
and PE2950 III systems just a week or two ago, I'm seeing some pretty 
strange behavior that I don't really understand.  With console 
redirection set to COM2, but redirection after boot disabled, and 
ISOLINUX / GRUB / Linux kernel configured to use the COM2 serial port 
(ttyS1), the Linux system and its boot helpers are getting tons of bogus 
data coming into the serial port - unless an SOL session has been 
established.

Running cat /dev/ttyS1 once Linux is up and running (this required 
disabling the serial port for ISOLINUX and GRUB), I am seeing lines like 
the following:

[SYS]

[ERR D5]

which make me think that somehow the BMC is in terminal mode and talking 
to the Linux kernel (RHEL 5.1) and boot utilities over the COM2 serial 
interface (and these messages are responses to the login or other 
prompts, and/or kernel echoing of input characters).  But I can't 
understand how that is happening.  Once an SOL session is established 
the chatter on the serial interface goes away.  I don't have the Dell 
OpenManage or BMC Utility installed, just the regular RHEL 5.1 RPMs 
(although the OpenIPMI drivers are loaded).

Has anyone seen any strange behavior like this, or have any ideas about 
how to disable it? (I don't think this is a hardware problem as I'm 
seeing it on all the new systems).  Any replies greatly appreciated.

@alex

-- 
mailto:alex.dupuy at mac.com