the following patch was just integrated into master: commit f91c8f290b2a723d1bda9a5dd7d668390672317e Author: Jens Rottmann JRottmann@LiPPERTembedded.de Date: Fri Mar 1 19:01:00 2013 +0100
FrontRunner/Toucan-AF: work around AGESA RAM init crashing on reboot
If you try to reset the system with outb(3,0x92), outb(4,0xcf9) or a triple-fault it will instead crash with a messy screen. As the more common outb(0xFE, 0x64) doesn't work with our setup, Linux will crash whenever you ask it to reboot. Closer inspection shows that on a warm boot of Coreboot agesawrapper_amdinitpost() always fails with error code 7. Looks like DDR3 re-init goes wrong somehow. I tried find the reason for this but was unable to. I am convinced this is not board specific but a bug in AGESA.
In the end I had to settle for a workaround: if amdinitpost returns 7 this patch resets the system harder with outb(0x06, 0x0cf9), after that RAM init will succeed. As amdinitpost is early in POST this automatic reset is quick enough not to be noticable.
I'd perfer a real fix, but that's all I have.
Change-Id: I4763254b489f42a135232e45328ecf0d5c4d961a Signed-off-by: Jens Rottmann JRottmann@LiPPERTembedded.de Reviewed-on: http://review.coreboot.org/2573 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer stefan.reinauer@coreboot.org
Build-Tested: build bot (Jenkins) at Fri Mar 1 21:58:08 2013, giving +1 Reviewed-By: Stefan Reinauer stefan.reinauer@coreboot.org at Sat Mar 2 00:18:08 2013, giving +2 See http://review.coreboot.org/2573 for details.
-gerrit