On Fri, 2010-01-29 at 18:54 +0000, Matthew Dharm wrote: > On Fri, Jan 29, 2010 at 08:51:47PM +0300, Sergei Shtylyov wrote: > > Catalin Marinas wrote: > > > > >That would be a more general solution rather than going through each HCD > > >driver since my understanding is that flush_dcache_page() is only needed > > >together with the mass storage support. > > > > Note that DMA capable driver can be doing some transfers in PIO mode > > or falling back to PIO mode if DMA mode transfer is unsuccessful (the > > musb driver is an example of the latter and if the DMA rewrite patches > > will get accepted, it'll do short transfers in PIO mode). > > Given that an HCD can choose, on the fly, if it's using DMA or PIO, the HCD > driver is the only place to reasonably put any cache-synchronization code. > > That said, what do the other SCSI HCDs do? I'm guessing the question gets > kinda muddy there, since the other SCSI HCDs all talk directly to some > piece of hardware, and thus are responsible for the cache management > themselves. > > Based on that, one could argue that ub and usb-storage should be doing > this. > > HOWEVER, I firmly believe that the cache-management functions belong with > the driver that actually talks to the low-level hardware, as that's the > only place where you can be 100% certain of what cache operations are > needed. After all, I think someone is working on a USB-over-IP transport, > and trying to manage cache at the usb-storage level in that scenario is > just silly. > > So, let's put this in the HCD drivers and be done with it. Doing this (flush_dcache_page) in the HCD driver (ISP1760) solves my problem. I'll post a patch and also cc the driver maintainer. Thanks. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
