Commit cbea6e5a authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: pcm: Check mmap capability of runtime dma buffer at first 

Currently we check only the substream->dma_buffer as the preset of the
buffer configuration for verifying the availability of mmap.  But a
few drivers rather set up the buffer in the own way without the
standard buffer preallocation using substream->dma_buffer, and they
miss the proper checks.  (Now it's working more or less fine as most
of them are running only on x86).

Actually, they may set up the runtime dma_buffer (referred via
snd_pcm_get_dma_buf()) at the open callback, though.  That is, this
could have been used as the primary source.

This patch changes the hw_support_mmap() function to check the runtime
dma buffer at first.  It's usually NULL with the standard buffer
preallocation, and in that case, we continue checking
substream->dma_buffer as fallback.

Link: https://lore.kernel.org/r/20210809071829.22238-2-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 2c86446f

sound/core/pcm_native.c

+7 −2
Original line number Diff line number Diff line
@@ -243,13 +243,18 @@ int snd_pcm_info_user(struct snd_pcm_substream *substream, 


static bool hw_support_mmap(struct snd_pcm_substream *substream)

{

	struct snd_dma_buffer *dmabuf;



	if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP))

		return false;



	if (substream->ops->mmap || substream->ops->page)

		return true;



	switch (substream->dma_buffer.dev.type) {

	dmabuf = snd_pcm_get_dma_buf(substream);

	if (!dmabuf)

		dmabuf = &substream->dma_buffer;

	switch (dmabuf->dev.type) {

	case SNDRV_DMA_TYPE_UNKNOWN:

		/* we can't know the device, so just assume that the driver does

		 * everything right
@@ -259,7 +264,7 @@ static bool hw_support_mmap(struct snd_pcm_substream *substream) 
	case SNDRV_DMA_TYPE_VMALLOC:

		return true;

	default:

		return dma_can_mmap(substream->dma_buffer.dev.dev);

		return dma_can_mmap(dmabuf->dev.dev);

	}

}