On Thursday 22 January 2009 04:26:22 am yogeshwar sonawane wrote: > If there are multiple PCIe cards of the same type, e.g. 3 or 4 network > controllers, in a node. > Now, if one allocates a buffer using pci_alloc_consistent() using > pci_dev struct of one of the card. > > 1) Whether that buffer can be used by remaining cards also ? Hi Yogeshwar, No. When you use pci_alloc_consistent() or any of the other DMA mapping services, the results are only valid for the device you specified. The other similar devices might be behind different IOMMUs, so you have to do separate calls for each device. Generally drivers are written to deal with each device completely separately, so there's little if any state shared between multiple cards of the same type. Bjorn > Whether DMA addresses returned by pci_alloc_consistent() can be used > by all the cards explained in above situation ? > > 2) What will be the case for multiple platforms/architectures ? > > 3) There can be multiple PCIe bridges giving multiple slots on some machines. > What will happen, when above situation is considered in such machines ? > > Any link of reference can be helpful. > > Thanking you, > Yogeshwar > -- > 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 -- 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
