Commit dc0dc8a7 authored Aug 08, 2021 by Takashi Iwai

ALSA: pcm: Fix mmap breakage without explicit buffer setup



The recent fix c4824ae7 ("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: c4824ae7 ("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>

parent 739d0959

sound/core/pcm_native.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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;