[syslinux] [RFC][PATCH] Gfxboot COMBOOT module

Sebastian Herbszt herbszt at gmx.de
Wed Jan 7 15:53:22 PST 2009

Steffen Winterfeldt wrote:
> a178235 wrote:
> > I hope that the work done on GFXBoot comes to fruition. Some of the
> > previous posted comments seemed negative and I hope that it doesn’t
> > discourage those involved from completing the module. I think that it
> > would be very beneficial as PXELINUX does not have this ability and
> > ISOLINUX does.
> I've sent a patch for the gfxboot.com module to Sebastian that addresses the
> file size issue. Also, the latest gfxboot at
> https://gfxboot.svn.sourceforge.net/svnroot/gfxboot/trunk works with files
> of unknown size. I've put the latest gfxboot.com patch I've seen in the
> patches directory for testing.

gfxboot.asm r27 in your repository is almost identical to the version i got
here with your patch applied. Minor difference is

@@ -320,7 +321,7 @@
                cmp ax,16
                jb skip_extended

-               mov word [gfx_xmem_0],81h       ; 1MB at 8MB
+               mov word [gfx_xmem_0],88h       ; 8MB at 8MB
                mov word [gfx_xmem_1],0a1h      ; 1MB at 10MB
                mov dword [gfx_save_area1],7f0000h      ; 8MB-64k

Can you explain this please? 8MB at 8MB does somewhat overlap
1MB at 10MB, not?

> I haven't seen any major issues during my tests.

It does work in qemu with pxelinux and a tftp server with tsize option support.
I get a triple fault as soon as i disable it tho.

qemu: fatal: triple fault
EAX=0006c900 EBX=00060000 ECX=ff6f1574 EDX=ffffffff
ESI=0006c9c4 EDI=0097b450 EBP=00000008 ESP=00065404
EIP=00001823 EFL=00000202 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0008 00000000 ffffffff 00cf9300
CS =0018 00050040 0000ffff 00409b05
SS =0008 00000000 ffffffff 00cf9300
DS =0020 00050040 0000ffff 00009305
FS =0008 00000000 ffffffff 00cf9300
GS =0008 00000000 ffffffff 00cf9300
LDT=0000 00000000 00000000 00008200
TR =0030 00002ec4 00000067 00008900
GDT=     00050910 00000047
IDT=     00800009 000007ff

> And as it currently looks I
> will discontinue the gfxboot patches for syslinux and go for the com module
> instead.

What about the "disksize" feature or the progress bar while loading? Do you intent
to drop those?

> Sebastian, are you still working on the module?

Depends on your definition of "work". The primary goal was to make the module good
enough to replace your patch, secondary to make it work with pxelinux. I want to make
that happen if time permits.

Steffen, is your syslinux-3.63.diff patch under the GPL 2? I think this could be the
license for the gfxboot module (if possible) since it contains parts of your gfxboot.inc
and also code from syslinux which is under the GPL 2. pxechain.asm got some license
information so i guess gfxboot.asm needs those too. hpa, is that acceptable?

- Sebastian

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