On Jul 20, 2011 10:55 AM, "Michael Büsch" <m@xxxxxxx> wrote: > > On Wed, 20 Jul 2011 08:16:08 +0200 > Rafał Miłecki <zajec5@xxxxxxxxx> wrote: > > > W dniu 20 lipca 2011 01:15 użytkownik Michael Büsch <m@xxxxxxx> napisał: > > > On Wed, 20 Jul 2011 00:12:20 +0200 > > > Rafał Miłecki <zajec5@xxxxxxxxx> wrote: > > >> + * be fixed on ssb side, but requires testing with b43, > > >> + * b43legacy and b44. */ > > > > > > No it doesn't. b44 and b43legacy don't use 64bit DMA. > > > Just fix it in ssb, please. > > > > They (drivers) don't, but what if we start giving them routing for > > 64-bit DMA? AFAIU they treat 64-bit DMA as 32-bit one (according to > > specs: "If 64 Bit isn't an option, Silicon Backplane and PCI-E buses > > can use 32 bit DMA."). > > > > Won't they start using 64-bit DMA in the 32-bit way but with 64-bit > > routing bits? > > > > I have no idea what you're talking about. > The fact is: These "temporary workarounds" tend to stay in the driver forever > if we don't fix it _now_. So please fix it now. > We know whether we are on 64bit DMA or not. So if we are on 64bit DMA, use the 64bit mask. > Simply pass the "32 or 64 bit" boolean flag to ssb_dma_translation() as parameter. > There's nothing that can go wrong here with older drivers. Sorry, for not explaining this well eno ugh. I'm afraid of situation where b44 driver supports 64-bit DMA device *without* handling this as such a device. It treats it as 32-bit one and it works thanks to kind of ssb's fallback described in the specs. Now if I clean ssb_dma_translation we will detect that DMA is 64-bit and we will pass different routing bit. So as the result b44 will still treat DMA as 32-bit one, but it will start using routing for 64-bit one. Alternative is to do not detect kind of DMA in the ssb_dma_translation but take it as a parameter (as you suggested). A *little* more to care about on the driver side but would make a trick. Or... is there any b44 supported device with 64-bit DMA at all? -- Rafał -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
