[syslinux] extlinux 6.03 IPMI SOL (serial-over-lan) console not responding to input

[Andrew J. Schorr]

Hi,

On Mon, May 18, 2015 at 10:09:12PM +0300, Ady via Syslinux wrote:
> First, you should add all the lib*.c32 files for BIOS (located under 
> the BIOS subdir), so to avoid the error messages.

Thanks.  But the problem was demonstrated in any case, regardless
of whether these files are present.  The input is not received
by extlinux.

> Then, just in case, have you tried changing:
> 
>  serial 0 115200 0x003 
> 
> with alternative values?

I previously tried different flowcontrol bits, such as 0 or 0x00b.

> For instance:
>  port is a number (0 =/dev/ttyS0 = COM1, etc.) or an I/O port address 
> (e.g. 0x3F8).

The port is certainly right -- the serial output is displayed correctly.
I cannot see how changing it to the wrong port would help.

Similarly, the speed is correct.  It works properly with the physical
serial connection, and it displays properly over IPMI.

> Or trying a different speed, just for a test?

I have not tried this.  It does not seem plausible that it could matter.
That being said, two of the three machines exhibiting the problem have the
speed configured at 115,200, and the other one is at 57,600.  So I have
effectively tried two different speeds.

> Or trying a different flowcontrol value for a test?

That was the first thing I tried.  It did not help.

> I am not saying it will certainly solve your situation (probably it 
> won't), and a bug in Syslinux 6.03 is not at all discarded.
> 
> The other suggestion I can think of would be to search for a BIOS 
> update.

I think I said this already, but for the sake of clarity: the exact
same extlinux.conf setup was working properly on the same machine with
the same motherboard and the same BIOS under Fedora 19 with extlinux 4.05.
The only thing that changed was upgrading the O/S (and extlinux along
with it).

> I am aware that these are not the type of comments you would hope for.

I appreciate your responding.  But I feel that I have done enough testing at
this point to demonstrate that there is a bug in extlinux 6.03's serial
implementation.  Grub2 works fine, and older extlinux works fine.

Should I bother to create a bugzilla for this?  I'm willing to run more
tests from which we have some hope of learning something.  But I respectfully
submit that most of your suggestions above are exceedingly unlikely to
reveal any additional useful information.  I've already done a lot of
troubleshooting, and I think I've narrowed down the problem pretty well.
The next step is to start looking at the code.  Is there a git repository
for this that can show the difference in the serial handling between 4.05
and 6.03?  I have been a maintainer on some open-source projects.  At
a certain point, enough information has been collected, and it's time to
dive into the code or find a way to get some debugging info.  I think
we have exhausted what can be learned from running tests with various
configurations.

Regards,
Andy