[syslinux] syslinux vs isolinux - com32 serial port output problem
Geert Stappers
stappers at stappers.nl
Thu May 12 10:45:08 PDT 2016
On Thu, May 12, 2016 at 06:16:46PM +0200, Good Old Idea via Syslinux wrote:
> On Thu, May 12, 2016 at 02:29:52PM +0000, Janz, Burt via Syslinux wrote:
> > I have a need to display text to COM2 before loading a kernel.
> > The easiest way to do this was to invade menu.c32 (menumain.c) and
> > add a function to send the string out to the serial port just before
> > the selected menu "label" is executed. In menumain.c, my function is
> > called just before 'if (cmdline)'.
> >
> >
> > The code I wrote to initialize the hardware and send individual
> > characters to COM2 works as expected when I boot from a USB drive
> > (syslinux): the text is seen on COM2. However, when I boot from the
> > CD, I don't see any output on COM2.?
> >
> >
> > syslinux.cfg and isolinux.cfg are identical. menu.c32 executes
> > properly on the CD, so I'm assuming that I have all the needed com
> > module support on the CD.
> >
> >
> > In both cases, the system boots up as expected. The only difference
> > appears to be the missing output on COM2 when booting from a CD. Yes,
> > I have tried this using different CD drives. I have even tried this
> > on a couple of different systems (a "final ship" and an open-frame
> > "test fixture").
> >
> >
> > Any ideas?
> >
>
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Thank you for doing so. Welcome to this project.
Back to ideas:
Tell more about the code that was added. How it was build.
Not that I have profound knowledge of Syslinux code base,
but thing I can tell is that sharing which function call was used,
will help.
What I guess that is wrong, is mixing modules from different builds.
Groeten
Geert Stappers
Member of the usual suspects, does non-subscribe-postings-approval
--
Leven en laten leven
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