Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 9 Apr 2010 16:25:33 -0400 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [LKML] Re: USB transfer_buffer allocations on 64bit systems |
| |
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.
| ![\](/images/icornerr.gif) |