[alsa-devel] [alsa-lib][PATCH] pcm: fix wrong document references to PCM APIs which perform direct memory access with frame copying

[Takashi Iwai]

On Sun, 11 Dec 2016 12:31:38 +0100,
Takashi Sakamoto wrote:
> 
> In a design of ALSA PCM interface, for PCM frame transmission to/from
> kernel space, applications can select from two options; direct memory access
> or ioctl(2). Available options are decided depending on device capacity and
> machine architecture. Applications can get available options by the first
> entry of 'struct snd_pcm_hw_params.masks'.
> 
> When the mask includes 'SNDRV_PCM_ACCESS_MMAP_xxx', applications can use
> direct memory access. For this use case, userspace library has two types
> of PCM API. One is to expose a pointer over the memory to start
> reading/writing PCM frames. Another is to copy PCM frames between the
> memory and a given buffer.
> 
> Current documentation includes wrong references to these APIs to describe
> their advantages/disadvantages. This confuses application developers
> because the references indicate PCM APIs to execute ioctl(2) operation to
> read/write PCM frames.
> 
> This commit fixes the bug.
> 
> Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>

Applied, thanks.


Takashi