Re: [PATCH] 2.4 use __dma_buffer in scsi.h

From: James Bottomley (
Date: Thu Jun 13 2002 - 12:52:39 EST said:
> Out of curiousity, how do you deal with someone writing to Scsi_Cmnd
> _before_ the DMA and having that data lost when pci_map_single() with
> PCI_DMA_FROMDEVICE invalidates the cache before writeback?

The the pci_map_single with PCI_DMA_FROMDEVICE is supposed to do a writeback
invalidate cycle on the cache when pci_sync_single is called (at least this is
how it is implemented on parisc) so any writes up to the sync point are
flushed to memory before the cache line is trashed.


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This archive was generated by hypermail 2b29 : Sat Jun 15 2002 - 22:00:29 EST