Hi roger > Using your latest tree still shows the packet checksum errors, despite >XLB snooping being enabled. > >I think that the cache flush is required > It really shouldn't be. Take a look at http://www.freescale.com/files/microcontrollers/doc/app_note/AN2604.pdf, page 3, 4th paragraph
quote : <<< In case the memory location interested by BestComm accesses are cached in copy-back mode by the core, a "Snooping" activity can be forced to the core, so that an 'address retry' will be issued and the core will first flush it's cache line before allowing BestComm to retry it's transaction. >>> Note that performance wise, adding it is probably a good idea. It will have to be flushed eventually and forcing BestComm to retry a transaction is just waste of XLB cycles ... >or >that the skb pages must be marked coherent somehow. > Yes they must. I haven't checked if they were but since this requirement is common for multiple ppc, I'd guess they are. >I note that the 8xx >fec.c file also has a cache flush, so it isn't that strange. > > I don't know 8xx in details, but in arch/ppc/Kconfig, 8xx defines NOT_COHERENT_CACHE symbol. So they probably excpect it not to be. Sylvain