[syslinux] extlinux: missing text on serial output

[Ferenc Wagner]

"H. Peter Anvin" <hpa at zytor.com> writes:

> Ferenc Wagner wrote:
>
>>>> Can somebody confirm that it's a bug?
>>>
>>> It's easy enough to see how the EBIOS would be missing - the
>>> banner is printed on the screen before the config file is written,
>>> so it's issued separately for the serial console.  The CR from the
>>> multiboot module is also reasonably easy to explain (it's a C
>>> environment, and at some point \n -> \r\n).  However, "say" not
>>> outputting on the serial console is weird and serious.  I will
>>> look into it.
>> 
>> What's the status of these issues?  Should I test a newer version
>> or rather shut up and send patches? :) Another interesting thing
>> (not sure if I've mentioned already) is that after dismissing the
>> boot: prompt there is a long delay (order of a minute) before
>> output starts appearing.  I'll investigate this further, just
>> wondered whether you'd got an idea.
>
> Hm, almost sounds like it's waiting for CTS.

It's very well possible that something is broken around the serial
connection.  There are two extra unknowns in the equation: the DRAC
III management card tapping the serial line and the Xen hypervisor
(but the latter is started by mboot.c32, so it can't influence the
output of that header).  I started work on eliminating each, but
weekend intervened.  If it's waiting for CTS (indeed I've got serial
0x2f8 57600 0x013), what determines the length timeout, after which
Extlinux sends the data anyway?

> I haven't had a chance to look into it at all, so if you have the
> opportunity to track things down and send patches, *please* do go
> ahead (against 3.70-pre14, please.)

Sure, that's always the case, I just wanted to avoid duplication of
work.  I expect to be able to investigate this shortly.  In case I
can't avoid touching the code, I'll work on the Git tree. :) Please
don't hesitate to share either educated or wild guesses as they strike
you.
-- 
Regards,
Feri.