On Mon, Mar 16, 2009 at 5:35 PM, FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> wrote: > On Mon, 16 Mar 2009 12:15:37 -0700 > "Luis R. Rodriguez" <mcgrof@xxxxxxxxx> wrote: > >> I've run into "PCI-DMA: Out of IOMMU space" messages after loading and >> unloading a module 30 times. The interesting thing is this only >> happens if I have > 4 GB of memory. The box this occurs has AMD Phenom >> quad core CPU so I take it a harware IOMMU is being used. Below are >> example relevant messages with > 4 GB and then < 4 GB of memory. The >> driver I tested this with was ath9k. It could be an issue perhaps with >> ath9k but I am unable to find an issue in our probe/removal. >> >> Could this be an issue with the AMD IOMMU used? Or is it more likely a >> driver issue? > > ath9k wants DMA_32BIT_MASK, right? If so, GART IOMMU does nothing on a > system with < 4GB memory since ath9k can access to all the memory > addresses directly. With >4GB memory, GART needs to remap an address > higher than 4GB because ath9k wants DMA_32BIT_MASK. > > From a quick look, ath9k doesn't call pci_unmap_single for rx > buffers. Though I might be wrong because I don't know anything about > the driver. You seem to be right actually, we were calling pci_unmap_single() for rx buffers on the RX tasklet but never for the simple case of removing the module. Will test it out in a bit. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
