> -----Original Message----- > From: Benjamin Herrenschmidt [mailto:b...@kernel.crashing.org] > > Hi Folks ! > > Is there any specific reason why you chose 1T (40 bit) as the location of > the 64-bit DMA window ? > > It happens that most current radeon adapters cannot DMA there, they have > a 40-bit DMA limit. I seem to be getting things to work fine using a 39- > bit window, but I suppose that might collide with something else ? T4240 has 40bit physical address ability. " This chip's 40-bit, physical address map consists of local space and external address space. For the local address map, 32 local access windows (LAWs) define mapping within the local 40-bit (1 TB) address space. Inbound and outbound translation windows can map the chip into a larger system address space such as the RapidIO or PCIe 64-bit address environment. This functionality is included in the address translation and mapping units (ATMUs).
" That should be the reason to set the DMA window to 40-bit. > > Can you guys consider changing the default ? Any collide for 40bit? Roy _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
