26 Oct
2010
26 Oct
'10
7:24 a.m.
On Tue, 26 Oct 2010, Manu Abraham wrote:
Hi,
I have been wondering how to interface a Scatter Gather region as a DMA buffer for an Audio Grabbing device. The device is a NOC type device, similar to a SOC, the audio grabber is a part of it, for realizing the audio capabilities on the device.
The hardware DMA is mostly a Scatter Gather based engine, and it can be described thus, briefly.
Use snd_pcm_lib_preallocate_pages_for_all() - type SNDRV_DMA_TYPE_DEV_SG and snd_pcm_sgbuf_* routines. Check hda_intel.c source for more details.
Jaroslav
----- Jaroslav Kysela perex@perex.cz Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc.