We've had a number of people reporting that their x86-64s stopped booting when they moved to 2.6.23. It rebooted just after discovering the AGP bridge as a result of the IOMMU init.
Martin tracked this down to the following commit. commit 2e1c49db4c640b35df13889b86b9d62215ade4b6 Author: Zou Nan hai <[EMAIL PROTECTED]> Date: Fri Jun 1 00:46:28 2007 -0700 x86_64: allocate sparsemem memmap above 4G On systems with huge amount of physical memory, VFS cache and memory memmap may eat all available system memory under 4G, then the system may fail to allocate swiotlb bounce buffer. There was a fix for this issue in arch/x86_64/mm/numa.c, but that fix dose not cover sparsemem model. This patch add fix to sparsemem model by first try to allocate memmap above 4G. Signed-off-by: Zou Nan hai <[EMAIL PROTECTED]> Acked-by: Suresh Siddha <[EMAIL PROTECTED]> Cc: Andi Kleen <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]> This should be probably be reverted for 2.6.23-stable, and either fixed properly in .24, or reverted there too. More info at https://bugzilla.redhat.com/show_bug.cgi?id=249174 Dave -- http://www.codemonkey.org.uk - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/