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Message-ID: <386072610811190200l576d7735rb0188ab53f5185fa@mail.gmail.com>
Date: Wed, 19 Nov 2008 18:00:36 +0800
From: "Bryan Wu" <cooloney@kernel.org>
To: "Takashi Iwai" <tiwai@suse.de>
Subject: [Question] Can I open a substream in kernel space without attach to a file pointer?
Cc: "ALSA devel" <alsa-devel@alsa-project.org>,
       LKML <linux-kernel@vger.kernel.org>
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Hi Takashi,

I am developing a USB gadget driver compliant to USB Audio Class Spec 2.0.
So I want to open a PCM substream and do some playback of capture,
then close them?

I found snd_pcm_open_substream() is for opening a substream and attach
it to a file.
But in my application, there is no need to open a file before opening
a substream.

- Is there any interface for me to open a substream in kernel space
without attach to a file?
- How to playback and capture in kernel space, use snd_pcm_lib_write
and snd_pcm_lib_read?
- How to get the snd_pcm_hardware struct from low level driver,
because I have to get the hardware configuration of the snd pcm
device?

And I am reading the code of OSS emulator in ALSA. It provides some
info about the kernel space sound card programming.

Thanks a lot
-Bryan