because we try to reserve dma32 early, so we have chance to get aperture
from 64M.
with some sequence aperture allocated from RAM, could become E820_RESERVED.
and then if doing a kexec with a big kernel that uncompressed size is above
64M we could have a range conflict with still using gart.
So allocate gart aperture from 512M instead.
Also change the fallback_aper_order to 5, because we don't have chance to get
2G or 4G aperture.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
7677b2ef6c