Dear Stas Sergeev, On Thu, 12 Mar 2015 16:03:07 +0300, Stas Sergeev wrote:
> > No, this is expected. Your physical address space is shared between RAM > > and I/O devices. So the space 0xf0000000 -> 0xffffffff in the physical > > address space is where all the registers for your SoC and PCIe devices > Yeah, I realize that, but I was hoping that some work-around > exists. For example, move entire dimm above 4G? Is this really > impossible? Or maybe move overlapping region above 8G... I am not aware of any trick that would allow to do that, but I have also never looked in the deep details of the Marvell memory controller and what's possible to do with it. Moving entire DIMM above 4G is clearly not possible: devices can only do DMA on the first 32 bits of the physical address space. So if you move all the physical memory above 4G, you don't have any memory left for DMA. Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- 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/
