Hello Benjamin, On Wed, Jun 17, 2009 at 3:08 AM, Benjamin Herrenschmidt<b...@kernel.crashing.org> wrote: > On Wed, 2009-06-17 at 02:56 +0200, Leon Woestenberg wrote: >> I use pci_map_sg(), have the device perform either DMA master reads or >> writes to the bus address using PCIe. >> After that, I use pci_unmap_sg(). >> >> My assumption is that pci_unmap_sg() either makes the cache coherent >> or invalidated and thus I do not need to take further actions. >> This is on a MPC83xx or 85xx system. >> >> Is this assumption correct? > > It is, as far as I understand things :-) Those APIs are fun. > > You should only need the explicit sync calls if you are going to peek or > poke at the DMA mapped memory before you unmap it. > Thanks, then at least I understand things in the corr^H^H^H^Hsame way :-)
And btw, I hadn't seen any data mismatch yet. Regards, -- Leon 'likewise' Woestenberg _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
