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ALSA: pcm: Fix mmap breakage without explicit buffer setup

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The recent fix c4824ae7db ("ALSA: pcm: Fix mmap capability check")
restricts the mmap capability only to the drivers that properly set up
the buffers, but it caused a regression for a few drivers that manage
the buffer on its own way.

For those with UNKNOWN buffer type (i.e. the uninitialized / unused
substream->dma_buffer), just assume that the driver handles the mmap
properly and blindly trust the hardware info bit.

Fixes: c4824ae7db ("ALSA: pcm: Fix mmap capability check")
Reported-and-tested-by: Jeff Woods <jwoods@fnordco.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/s5him0gpghv.wl-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2021-08-08 09:01:16 +02:00
parent 739d0959fb
commit dc0dc8a73e
1 changed files with 4 additions and 1 deletions
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5
sound/core/pcm_native.c
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@ -251,7 +251,10 @@ static bool hw_support_mmap(struct snd_pcm_substream *substream)
switch (substream->dma_buffer.dev.type) {
case SNDRV_DMA_TYPE_UNKNOWN:
return false;
/* we can't know the device, so just assume that the driver does
* everything right
*/
return true;
case SNDRV_DMA_TYPE_CONTINUOUS:
case SNDRV_DMA_TYPE_VMALLOC:
return true;