[syslinux] extlinux: missing text on serial output

[H. Peter Anvin]

Ferenc Wagner wrote:
> 
> fixes this issue on syslinux and extlinux.  Pxelinux doesn't exhibit
> this issue, it prints the say message either way.  I couldn't test
> isolinux.  Also I can't tell if it's the correct fix, because I got
> lost between the dozens of output functions, but this will probably be
> obvious for you.
> 

Yes, and so it is.

In fact, this is so obvious that I am going to change the names:

	writestr -> early_writestr
	cwritestr -> writestr

... to better reflect what these functions actually do.

PXELINUX and ISOLINUX have writestr == cwritestr so are unaffected.

>>> after dismissing the boot: prompt there is a long delay (order of a
>>> minute) before output starts appearing.
>> Hm, almost sounds like it's waiting for CTS.
> 
> I've found something which may be related.  It's not connected to
> serial at all.  Here's my full config:
> 
> say hello
> 
> There's no file named linux on the floppy image, so both syslinux and
> extlinux complain: "Could not find kernel image: linux".  However,
> syslinux does this instantly, while extlinux "waits" for a couple of
> seconds (running under QEMU) before printing this message.  If I
> enable DEBUG_TRACERS (a wonderful debugging aid, thanks for putting it
> into place!) extlinux floods my terminal with 288 kB of 'H's before
> outputting the message.  Those seem to come from cache.inc.  I doubt
> this would be normal.  What do you think?

It is obviously looping on something, reading the same thing over and 
over.  I'll see if I can reproduce it.

	-hpa