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[ALSA] usb-audio - Fix AC3 with M-Audio Audiophile USB 

Fixed AC3 interface in device_setup=0x00 mode thanks to Hakan
Lennestal and updated documentation

Signed-off-by: Thibault Le Meur <Thibault.LeMeur@supelec.fr>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
This commit is contained in:
Thibault Le Meur 2007-07-13 11:50:23 +02:00 committed by Jaroslav Kysela
parent 1b290a510c
commit cac19c3ba1
2 changed files with 28 additions and 7 deletions
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22
Documentation/sound/alsa/Audiophile-Usb.txt
View File

@ -1,4 +1,4 @@
Guide to using M-Audio Audiophile USB with ALSA and Jack v1.4
Guide to using M-Audio Audiophile USB with ALSA and Jack v1.5
========================================================
Thibault Le Meur <Thibault.LeMeur@supelec.fr>
@ -12,6 +12,8 @@ History
- Added Low Endianness nature of 16bits-modes
found by Hakan Lennestal <Hakan.Lennestal@brfsodrahamn.se>
- Modifying document structure
* v1.5 - Thibault Le Meur (2007-07-12)
- Added AC3/DTS passthru info
1 - Audiophile USB Specs and correct usage
@ -105,9 +107,12 @@ way (I suppose the device's index is 1):
In this mode, the device uses Big Endian byte-encoding so that
supported audio format are S16_BE for 16-bit depth modes and S24_3BE for
24-bits depth mode. One exception is the hw:1,2 port which is reported
to be Little Endian compliant (supposedly supporting S16_LE) but processes
in fact only S16_BE streams.
24-bits depth mode.
One exception is the hw:1,2 port which was reported to be Little Endian
compliant (supposedly supporting S16_LE) but processes in fact only S16_BE streams.
This has been fixed in kernel 2.6.23 and above and now the hw:1,2 interface
is reported to be big endian in this default driver mode.
Examples:
* playing a S24_3BE encoded raw file to the Ao port
@ -116,6 +121,8 @@ Examples:
% arecord -D hw:1,1 -c2 -t raw -r48000 -fS24_3BE test.raw
* playing a S16_BE encoded raw file to the Do port
% aplay -D hw:1,1 -c2 -t raw -r48000 -fS16_BE test.raw
* playing an ac3 sample file to the Do port
% aplay -D hw:1,2 --channels=6 ac3_S16_BE_encoded_file.raw
If you're happy with the default Alsa driver mode and don't experience any
issue with this mode, then you can skip the following chapter.
@ -205,13 +212,16 @@ mode" above for an aplay command example)
3.2.1.3 - AC3 w/ DTS passthru mode
This mode is untested, I have no AC3 compliant device to test it. I uses:
Thanks to Hakan Lennestal, I now have a report saying that this mode works.
* device_setup=0x03
- 16bits 48kHz mode with only the Do port enabled
- AC3 with DTS passthru (not tested)
- AC3 with DTS passthru
- Caution with this setup the Do port is mapped to the pcm device hw:1,0
The command line used to playback the AC3/DTS encoded .wav-files in this mode:
% aplay -D hw:1,0 --channels=6 ac3_S16_LE_encoded_file.raw
3.2.2 - How to use the device_setup parameter
----------------------------------------------

13
sound/usb/usbaudio.c
View File

@ -2532,7 +2532,18 @@ static int parse_audio_format_i(struct snd_usb_audio *chip, struct audioformat *
* but we give normal PCM format to get the existing
* apps working...
*/
pcm_format = SNDRV_PCM_FORMAT_S16_LE;
switch (chip->usb_id) {
case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
if (device_setup[chip->index] == 0x00 &&
fp->altsetting == 6)
pcm_format = SNDRV_PCM_FORMAT_S16_BE;
else
pcm_format = SNDRV_PCM_FORMAT_S16_LE;
break;
default:
pcm_format = SNDRV_PCM_FORMAT_S16_LE;
}
} else {
pcm_format = parse_audio_format_i_type(chip, fp, format, fmt);
if (pcm_format < 0)