From: Takashi Iwai <tiwai@suse.de> stable inclusion from stable-5.10.59 commit 98c3fa3a9d7a2e405ad5a656793d0117bed00881 bugzilla: 176988 https://gitee.com/openeuler/kernel/issues/I4EAR4 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit dc0dc8a73e8e4dc33fba93dfe23356cc5a500c57 upstream. The recent fix c4824ae7db41 ("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: c4824ae7db41 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- sound/core/pcm_native.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index b36c8d94d4da..c5ef5182fcf1 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -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; -- 2.20.1