On Sat, 2010-05-22 at 06:12 -0600, Matthew Wilcox wrote: > On Sat, May 22, 2010 at 12:26:15PM +0200, Stefan Richter wrote: > > Hi, > > > > I came across a report of the subject message. What does it mean; what > > type of bug should be look for? > > > > https://bugzilla.redhat.com/show_bug.cgi?id=587178 > > >>> > > firewire_ohci 0000:04:00.4: PCI INT C -> GSI 16 (level, low) -> IRQ 16 > > firewire_ohci 0000:04:00.4: setting latency timer to 64 > > firewire_ohci: Added fw-ohci device 0000:04:00.4, OHCI version 1.0 > > DRHD: handling fault status reg 2 > > DMAR:[DMA Read] Request device [04:00.0] fault addr fffff000 > > DMAR:[fault reason 02] Present bit in context entry is clear > > DMAR:[DMA Read] Request device [04:00.0] fault addr fffff000 > > DMAR:[fault reason 02] Present bit in context entry is clear > > DMAR:[DMA Read] Request device [04:00.0] fault addr fffff000 > > DMAR:[fault reason 02] Present bit in context entry is clear > > <<< > > > > The log sounds as if this happens during from-device DMA of 04:00.4 into > > a consistent buffer, yet the fault is logged for device 04:00.0. The > > log is from a Dell M4500. The devices are, according to a web search, > > 04:00.0 CardBus bridge [0607]: Ricoh Co Ltd Device [1180:e476] (rev 02) > > 04:00.4 FireWire (IEEE 1394) [0c00]: Ricoh Co Ltd Device [1180:e832] > > (rev 03) (prog-if 10) > > I would guess that the DMAR can't distinguish between the different > devices behind the Cardbus bridge. Adding Dave Woodhouse. Yeah, the DMAR looks at the source-id in the PCIe transactions, and it sounds like those are all 04:00.0. But we've probably set up the DMAR to allow the transactions from 04:00.4, and then it naturally faults when a "different" device actually ends up doing the transaction. If you make the pci_find_upstream_pcie_bridge() function do the appropriate thing for this device, does it then work as expected? Whether that's a _sane_ thing to do or not is possibly more of a Jesse question... -- David Woodhouse Open Source Technology Centre David.Woodhouse@xxxxxxxxx Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
