Am Mittwoch, 24. Februar 2010 03:48:09 schrieb Benjamin Herrenschmidt: > On Fri, 2010-02-19 at 21:53 +0100, Oliver Neukum wrote: > > Am Freitag, 19. Februar 2010 18:36:51 schrieb Catalin Marinas: > > > If a page is already mapped in user space, flush_dcache_page() on ARM > > > does the flushing rather than deferring it to update_mmu_cache(). The > > > PIO HCD drivers, however, don't call flush_dcache_page(). Is it possible > > > that the HCD could transfer data into a page cache page already mapped > > > in user space? My understanding is that the scenario above is possible. > > > > Yes, video drivers do that. > > In which case it would be up to the video driver to call > flush_dcache_page() (though if it's v4l you are talking about, maybe it > might make sense to push it into the v4l layer itself). I don't know. The issue seems quite complex. It would seem better to centralize it as far as practical. Do you have a wrapper drivers could call? Regards Oliver -- 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
