Messages in this thread | | | Date | Thu, 03 Jan 2008 19:43:39 -0600 | From | Robert Hancock <> | Subject | Re: sata_nv + ADMA + Samsung disk problem |
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Benjamin Herrenschmidt wrote: >> Another thing about the PacDigi core: one has to be very careful >> to avoid sequential accesses to sequential PCI locations when >> programming the chip -- it cannot handle merged register writes. >> >> So for any group of sequentially laid out registers, the code has >> to ensure it never writes two adjacent registers in sequence.. > > Ugh ? Write combining isn't permitted on normal registers afaik... > > Ben.
Byte merging can be done by the chipset on MMIO writes (merging multiple 8 or 16-bit writes into a single 32-bit cycle).
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