[LAU] make alsa device hw:1,0 be hw:0,0 somehow

[Paul Davis]

This can be hard to do. Why can't you tell software to use hw:1 ?

Most system BIOS setup utilities can be used to disable onboard sound.
Getting Linux to reorder them is also possible but can be complex
depending on the types of devices (PCI, USB etc)

On Sun, Oct 4, 2015 at 2:57 PM, ansible <bburdette at gmail.com> wrote:
> I compiled supercollider to play through portaudio rather than jack, as it
> usually does, in an attempt to reduce latency and hassle.  It works for
> audio device hw:0,0, but it doesn't work for hw:1,0.  My problem is that on
> my device hw:0,0 has horrible latency - 70ms - while hw:1,0 has 9ms latency,
> much better.
>
> So what I'd like to do is reorder the audio devices, or disable the onboard
> audio, and have my current hw:1,0 be the hw:0,0 device.  Hopefully then
> supercollider will work with it and I'll have those coveted low latency
> numbers.  This is on arch linux on a bananapi armv7 computer.
>
> So here's the output from aplay -l:
>
> ```
> [bananapi at lemaker ~]$ aplay -l
> **** List of PLAYBACK Hardware Devices ****
> card 0: sunxicodec [sunxi-CODEC], device 0: M1 PCM [sunxi PCM]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> card 1: Pro [Sound Blaster X-Fi Go! Pro], device 0: USB Audio [USB Audio]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> [bananapi at lemaker ~]$
> ```
>
> According to the [alsa wiki][1], I should be able to reorder the devices
> using a .conf file. See 'set the default sound card'.  It gives the example
> of this:
>
> ```
> /etc/modprobe.d/alsa-base.conf
>
> options snd_mia index=0
> options snd_hda_intel index=1
> ```
>
> Ok so I made a file like that, but I only know the name of the usb driver,
> not the onboard sound driver.  lsmod reveals the following:
>
> ```
> [bananapi at lemaker ~]$ lsmod
> Module                  Size  Used by
> snd_usb_audio          96225  0
> snd_hwdep               5757  1 snd_usb_audio
> snd_usbmidi_lib        18033  1 snd_usb_audio
> cdc_acm                20518  0
> spidev                  6217  0
> spi_sun7i              17802  0
> sunxi_cedar_mod         9808  0
> mali_drm                2608  0
> drm                   209226  1 mali_drm
> mali                  111427  0
> disp_ump                 861  0
> ump                    52415  2 mali,disp_ump
> ap6210                584133  0
> ip_tables              12937  0
> x_tables               17443  1 ip_tables
> ```
>
> If I do "modprobe -r snd_usb_audio", then snd_hwdep and snd_usbmidi_lib both
> disappear too, so they are all for the same device I think.  That leaves
> nothing for the driver name for the onboard audio.
>
> The alsa wiki says that the driver names should be in "cat
> /proc/asound/modules" but I don't have that directory on my system.
>
> So anyway I made an alsa-base.conf file as directed, which looks like this:
>
> ```
> [bananapi at lemaker ~]$ cat /etc/modprobe.d/alsa-base.conf
> options snd_usb_audio index=0
> options sunxicodec index=1
> [bananapi at lemaker ~]$
> ```
>
> After creating that file and rebooting aplay just returns this.
>
> ```
> [bananapi at lemaker ~]$ aplay -l
> **** List of PLAYBACK Hardware Devices ****
> card 0: sunxicodec [sunxi-CODEC], device 0: M1 PCM [sunxi PCM]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> [bananapi at lemaker ~]$
> ```
>
> So this alsa-base.conf has the effect of making only the onboard audio
> available instead of reordering.  I most likely have the 'sunxicodec' name
> wrong for the onboard audio, I'm just guessing at that, and have no idea
> what the driver name for that is, if there even is one.  I'm kind of
> suspecting the audio device is part of a monolithic driver for the whole
> system-on-chip, is that possible?
>
>   [1]:
> https://wiki.archlinux.org/index.php/Advanced_Linux_Sound_Architecture
>
>
>
> --
> View this message in context: http://linux-audio.4202.n7.nabble.com/make-alsa-device-hw-1-0-be-hw-0-0-somehow-tp97402.html
> Sent from the linux-audio-user mailing list archive at Nabble.com.
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