At Fri, 26 Sep 2008 19:30:45 +0900, Paul Mundt wrote: > > On Fri, Sep 26, 2008 at 12:04:23PM +0200, Takashi Iwai wrote: > > At Thu, 25 Sep 2008 15:55:53 +0100, > > Pawel MOLL wrote: > > > > > > > One thing we can try is a patch like below. But, I'm not sure whether > > > > this is correct over all architectures, too. At best, a generic API > > > > would be helpful for such a thing... > > > > + area->vm_page_prot = pgprot_noncached(area->vm_page_prot); > > > > > > Well, it's not enough, because the kernel mapping of buffer is still > > > cached... A hack below does the job, but it is not nice as well... > > > > Yeah, that's not sexy, but maybe the only working case right now > > (better with arch-specific ifdefs). > > > > IIRC, a similar buffer handling (via vmalloc) is used in video > > drivers. I suppose they don't work as well, right? > > DRM driver uses __vmalloc() with PAGE_KERNEL_NOCACHE, but it's only > > for PPC32 non-coherent. > > > x86 does it also, via its PAGE_AGP definition. Right, but it doesn't seem for pages allocated via vmalloc() as in drm_scatter.c. > There are not that many platforms that define PAGE_KERNEL_NOCACHE though, > so this gets a bit messy.. Indeed. We really need to have a generic API for this kind of things... thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
