• Takashi Iwai's avatar
    ALSA: memalloc: Add non-cached buffer type · 42e748a0
    Takashi Iwai authored
    In some cases (mainly for x86), we need the DMA coherent buffer with
    non-cached pages.  Although this has been done in each driver side
    like HD-audio and intel8x0, it can be done cleaner in the core memory
    allocator.
    
    This patch adds the new types, SNDRV_DMA_TYPE_DEV_UC and
    SNDRV_DMA_TYPE_DEV_UC_SG, for allocating such non-cached buffer
    pages.  On non-x86 architectures, they work as same as the standard
    SNDRV_DMA_TYPE_DEV and *_SG.
    
    One additional change by this move is that we can assure to pass the
    non-cached pgprot to the vmapped buffer, too.  It eventually fixes the
    case like non-snoop mode without mmap access on HD-audio.
    Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    42e748a0
sgbuf.c 4.49 KB