On Wed, 2006-04-12 at 00:30 +0200, Benoit Boissinot wrote: > On Wed, Apr 12, 2006 at 08:21:17AM +1000, Benjamin Herrenschmidt wrote: > > > > > I still think we shouldn't reward shit hardware by complicating > > > up our DMA mappings internals. :-) > > > > BTW. In the meantime, can't that driver work in PIO only mode ? > > yes, I think you just have to have the pci_set_dma_mask fail with > DMA30BIT_MASK.
Ok, _that_ makes sense in fact to have ppc do that when the mask is too big... now the problem is should I compare the mask to the available RAM ? That is, there is little point in failing for a 30 bits mask if hte machine only has 512M of RAM. By extension of the above, what to do on 32 bits kernels, should I test the mask against total memory or specifically against lowmem ? There is no clear answer here as some drivers will get highmem pages for DMA, just not network drivers afaik (block drivers will), though I can't be sure what will happen with thing like nbd... I'm not familiar enough with the network stack. It would be sad to have 32 bits laptop switch to PIO when they have too much RAM if, in practice, skbs are always only in lowmem.. I think for now, what I may do is just add such a test for ppc64 and not ppc32 and will talk to paulus see if he happens to have a better idea. It's all very sad that bcm gets away with such crap though and that so many vendors just bought it without complaining... Ben. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
