On Tue, 2013-03-26 at 17:12 +0100, Clemens Ladisch wrote: > Peter Hurley wrote: > > Quadlet reads to memory above 4GB is painfully slow when serviced > > by the AR DMA context. In addition, the CPU(s) may be locked-up, > > preventing any transfer at all. > > Using physical DMA prevents the use of that address space for software > address handlers, so you have adjust the low_memory_region start in > core-transaction.c.
Right, thanks for pointing that out. > > Write the PhyUpperBound register with the end-of-memory value. If > > end-of-memory is beyond the OHCI limit of 0x0000ffff00000000, > > clamp to that value. > > You will have to lower this limit; there are protcols that assume that > addresses like 0xecc000000000 are available for software. Maybe 0x0000e80000000000 is a better maximum upper bound? Regards, Peter Hurley -- 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/
