On Sat, Apr 24, 2010 at 08:26:45PM +0200, Patrick Georgi wrote: > Am 24.04.2010 19:43, schrieb xdrudis:
> They might just use a watchdog: > - BIOS 1 sets a flag > - BIOS 1 configures the watchdog to trigger when it's not touched within > 2 seconds (or whatever). watchdog would reboot the system then > - BIOS 1 jumps in BIOS 2 > - BIOS 2 does whatever it needs to do to consider itself "safe" > - Meanwhile, BIOS 2 touches the watchdog every so often > - BIOS 2 deactivates the watchdog > > In this scenario, coreboot would have to know how to tell the watchdog > to reset its countdown, and how to disable the watchdog, to safely use > the Dual BIOS feature. > Ok. I'm rereading the link Gigabyte gave me, which does not explain enough or I don't understand it enough, but it might be this scenario you explain http://www.gigabyte.com.tw/FileList/NewTech/2006_motherboard_newtech/article_04_bios_explained.htm (the URL says 2006 but it was given to me in a mail in early March 2010) I've noticed they say it reboots before running the other BIOS, it's not just a jump. How would that work ? would it be some flag in CMOS ? This is better, I guess in that it gives both BIOSes the same initial state. It also says the original BIOS checks both BIOS copies, but I guess it doesn't matter since it will only run if coreboot fails, and then you have to reflash it anyway. > The feature supposedly shouldn't just guard against non-Gigabyte images, > but against issues with their own images, too - and those would have the > right signature, and thus would pass any such test. > > I'd be really amazed if they'd add another chip (that actually costs > money) and then only implement an incomplete protection scheme with it. > Ok. It makes sense. Thank you for explaining. -- coreboot mailing list: coreboot@coreboot.org http://www.coreboot.org/mailman/listinfo/coreboot
