Well, I'm not sure I'd want to pollute the tree with this sort of hack, but on the other hand it makes things work that wouldn't otherwise.
Does anyone think it's a good idea to commit the following patch: diff -urN /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/mm/cachemap.c linux-grinch/arch/ppc/mm/cachemap.c --- /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/mm/cachemap.c Thu Mar 14 13:49:01 2002 +++ linux-grinch/arch/ppc/mm/cachemap.c Wed Apr 3 11:51:30 2002 @@ -137,7 +137,18 @@ case PCI_DMA_NONE: BUG(); case PCI_DMA_FROMDEVICE: /* invalidate only */ +#ifdef CONFIG_USB + /* The USB stack is broken in that it uses DMA buffers + on the stack which are on the stack and not + cacheline aligned. That means cache invalidates + before DMA transfers corrupt the stack on machines + without DMA-consistent cache. This is a nasty + workaround until the USB layer is fixed (apparently + done in 2.5). */ + flush_dcache_range(start, end); +#else invalidate_dcache_range(start, end); +#endif break; case PCI_DMA_TODEVICE: /* writeback only */ clean_dcache_range(start, end); -- David Gibson | For every complex problem there is a david at gibson.dropbear.id.au | solution which is simple, neat and | wrong. -- H.L. Mencken http://www.ozlabs.org/people/dgibson ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/