Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 9 Apr 2010 17:23:22 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [LKML] Re: USB transfer_buffer allocations on 64bit systems |
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On Fri, 9 Apr 2010, Konrad Rzeszutek Wilk wrote:
> On Fri, Apr 09, 2010 at 03:34:06PM -0400, Alan Stern wrote: > > On Fri, 9 Apr 2010, Pedro Ribeiro wrote: > > > > > > The DMA pointers do indeed look sane. I wanted to take a deeper look at > > > > this and set up a 64bit system today. However, I fail to see the problem > > > > here. Pedro, how much RAM does your machine have installed? > > > > > It has 4 GB. > > > > That means DMA mapping cannot be the cause of the problem. :-( > > That isn't entirely true. The BIOS usually allocates a 256 MB ACPI/PCI hole > that is under the 4GB. > > So end up with 3.7 GB, then the 256MB hole, and then right above the 4GB > you the the remaining memory: 4.3GB.
How can Pedro find out what physical addresses are in use on his system?
Alan Stern
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