[ALSA] Support all sample rate conversion capabilities of DXS channels
Documentation,VIA82xx driver
Add support for full sample rate conversion capabilities of DXS
channels present in VIA VT8233/5/7 controllers:
- any sample rate in the 8000 ... 48000 Hz range is supported even if
the AC'97 codec supports only 48000 Hz output;
- different DXS channels can use different sample rates at the same
time (the controller performs required sample rate conversion and
mixing in hardware).
Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index 71ef049..c69581c 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -1211,16 +1211,18 @@
------------------
Module for AC'97 motherboards based on VIA 82C686A/686B, 8233,
- 8233A, 8233C, 8235 (south) bridge.
+ 8233A, 8233C, 8235, 8237 (south) bridge.
mpu_port - 0x300,0x310,0x320,0x330, otherwise obtain BIOS setup
[VIA686A/686B only]
joystick - Enable joystick (default off) [VIA686A/686B only]
ac97_clock - AC'97 codec clock base (default 48000Hz)
dxs_support - support DXS channels,
- 0 = auto (defalut), 1 = enable, 2 = disable,
- 3 = 48k only, 4 = no VRA
- [VIA8233/C,8235 only]
+ 0 = auto (default), 1 = enable, 2 = disable,
+ 3 = 48k only, 4 = no VRA, 5 = enable any sample
+ rate and different sample rates on different
+ channels
+ [VIA8233/C, 8235, 8237 only]
ac97_quirk - AC'97 workaround for strange hardware
See the description of intel8x0 module for details.
@@ -1232,18 +1234,21 @@
default value 1.4. Then the interrupt number will be
assigned under 15. You might also upgrade your BIOS.
- Note: VIA8233/5 (not VIA8233A) can support DXS (direct sound)
+ Note: VIA8233/5/7 (not VIA8233A) can support DXS (direct sound)
channels as the first PCM. On these channels, up to 4
- streams can be played at the same time.
+ streams can be played at the same time, and the controller
+ can perform sample rate conversion with separate rates for
+ each channel.
As default (dxs_support = 0), 48k fixed rate is chosen
except for the known devices since the output is often
noisy except for 48k on some mother boards due to the
bug of BIOS.
- Please try once dxs_support=1 and if it works on other
+ Please try once dxs_support=5 and if it works on other
sample rates (e.g. 44.1kHz of mp3 playback), please let us
know the PCI subsystem vendor/device id's (output of
"lspci -nv").
- If it doesn't work, try dxs_support=4. If it still doesn't
+ If dxs_support=5 does not work, try dxs_support=1; if it
+ doesn't work too, try dxs_support=4. If it still doesn't
work and the default setting is ok, dxs_support=3 is the
right choice. If the default setting doesn't work at all,
try dxs_support=2 to disable the DXS channels.