[SOLVED] USB Sound card no longer working

Question

I have used a Focusrite Scarlett 2i2, a USB audio interface, as my default sound card for the last two months or so. Its output comprises two RCA jacks. I have a cable that is two RCA male leads on one end and an 1/8" on the other. I use this cable all over the house, so I unplug it often. The USB device remains connected. Last night, while plugging the cable back into the device, I jostled the USB and the device lost power momentarily. Since then, ALSA has not been able to "see" the device. The device is, and always has been, plugged into a D-Link USB hub, which goes into the computer.
I did pacman -Syu and rebooted to no avail.
uname -r
3.15.1-1-ARCH
lsusb | grep -i focusrite
Bus 001 Device 005: ID 1235:8006 Focusrite-Novation Focusrite Scarlett 2i2
modinfo snd_usb_audio
http://pastebin.com/CEMr6Gif
cat /etc/modprobe.d/alsa-base.conf
#options snd slots=snd_usb_audio,snd_hda_intel
options snd_hda_intel index=-2
options snd_usb_audio index=0
The first line I recently commented out as an experiment. If this line is left in, ALSA attempts to use snd_usb_audio and when I run alsamixer it complains that it can't find the device. If this line is commented out, ALSA ends up using the on-board sound. Particularly, it uses 'HDA ATI HDMI'. There are two choices: HDA ATI HDMI and HDA ATI SB. When I was using the on-board sound, I was using HDA ATI SB.
cat /proc/asound/modules
0 snd_hda_intel
1 snd_hda_intel
lspci -nn | grep -i audio
00:14.2 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] SBx00 Azalia (Intel HDA) [1002:4383]
01:05.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] RS880 HDMI Audio [Radeon HD 4200 Series] [1002:970f]
aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: HDMI [HDA ATI HDMI], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: SB [HDA ATI SB], device 0: ALC889A Analog [ALC889A Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: SB [HDA ATI SB], device 1: ALC889A Digital [ALC889A Digital]
Subdevices: 1/1
Subdevice #0: subdevice #0
lsmod | grep '^snd'
snd_hda_codec_realtek 48535 1
snd_hda_codec_generic 50352 1 snd_hda_codec_realtek
snd_hda_codec_hdmi 36976 1
snd_hda_intel 18830 0
snd_hda_controller 19667 1 snd_hda_intel
snd_hda_codec 91154 5 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_intel,snd_hda_controller
snd_hwdep 5162 1 snd_hda_codec
snd_pcm 68932 4 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel,snd_hda_controller
snd_timer 15678 1 snd_pcm
snd 46421 8 snd_hda_codec_realtek,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_hda_codec_generic,snd_hda_codec,snd_hda_intel
ls -l /dev/snd
total 0
drwxr-xr-x 2 root root 80 Jun 26 10:13 by-path
crw-rw----+ 1 root audio 116, 2 Jun 26 10:13 controlC0
crw-rw----+ 1 root audio 116, 5 Jun 26 10:13 controlC1
crw-rw----+ 1 root audio 116, 4 Jun 26 10:13 hwC0D0
crw-rw----+ 1 root audio 116, 11 Jun 26 10:13 hwC1D0
crw-rw----+ 1 root audio 116, 3 Jun 26 10:13 pcmC0D3p
crw-rw----+ 1 root audio 116, 7 Jun 26 10:13 pcmC1D0c
crw-rw----+ 1 root audio 116, 6 Jun 26 10:13 pcmC1D0p
crw-rw----+ 1 root audio 116, 9 Jun 26 10:13 pcmC1D1c
crw-rw----+ 1 root audio 116, 8 Jun 26 10:13 pcmC1D1p
crw-rw----+ 1 root audio 116, 10 Jun 26 10:13 pcmC1D2c
crw-rw----+ 1 root audio 116, 1 Jun 26 10:13 seq
crw-rw----+ 1 root audio 116, 33 Jun 26 10:13 timer
All this information was collected while the device has been connected to the computer. Any help is greatly appreciated. Thanks!
Last edited by gluelogic (2014-07-01 21:36:19)

Answer 1

emeres wrote:You only ruled out hardware failure on the device side.
This is painfully true. This morning, I realized I didn't even check the D-Link. The LEDs on the interface were lit up from the USB connection, but the AC adapter was faulty. I replaced that, restored my original configuration by removing the # from the first line of my alsa-base.conf, and now everything is working again. The D-Link was simply unable to provide the device with enough power to operate.