[syslinux] SOLUTION: Version 3.35 problems with Broadcom BCM5780 chipset

[H. Peter Anvin]

Ole Holm Nielsen wrote:
> In this thread:
>    http://syslinux.zytor.com/archives/2007-February/008014.html
> I reported that IBM Opteron servers with Broadcom BCM5780 chipsets
> would freeze randomly in the PXE menus from the SYSLINUX 3.35
> tools vesamenu.c32 and menu.c32.  There did not seem to be any
> reason for this nor systematics in when the servers would lock up.
> 
> The solution is now available:  Upgrade your IBM servers to the
> latest Broadcom firmware released by IBM on May 21, 2007 !
> The IBM web-page is at
> http://www-304.ibm.com/jct01004c/systems/support/supportsite.wss/docdisplay?lndocid=MIGR-53693&brandind=5000008
> 
> There is no hint what Broadcom did to solve our PXE problem,
> but the menu.c32 certainly works without any glitch now.
> It should be noted that we have also upgraded the system BIOS
> to the latest release, but I haven't determined if the BIOS
> level has any influence on the PXE menu problem.
> 

My guess would be that they touched memory they shouldn't have.  This is
unfortunately an easy trap to fall into, simply because the PXE spec
implies that you can do something that is absolutely forbidden, which is
to use BMM-allocated memory after INT 19h has executed (BMM is the boot
memory manager, which by definition doesn't exist after the transition
to operating system execution, which happens at the point of INT 19h
execution.)

	-hpa