Been trying to get USB microphone on my webcam to work but no luck. Using Mythbuntu (Ubuntu 10.10/2.6.35 Alsa 1.0.23)

Command being used:
arecord -vv -D plughw:1,0 -f S16_LE -d 1 /dev/null

Output:
Recording WAVE '/dev/null' : Signed 16 bit Little Endian, Rate 8000 Hz, Mono
Plug PCM: Hardware PCM card 1 'USB Device 0x46d:0x8b2' device 0 subdevice 0
Its setup is:
stream : CAPTURE
access : RW_INTERLEAVED
format : S16_LE
subformat : STD
channels : 1
rate : 8000
exact rate : 8000 (8000/1)
msbits : 16
buffer_size : 4000
period_size : 1000
period_time : 125000
tstamp_mode : NONE
period_step : 1
avail_min : 1000
period_event : 0
start_threshold : 1
stop_threshold : 4000
silence_threshold: 0
silence_size : 0
boundary : 2097152000
appl_ptr : 0
hw_ptr : 0
arecord: pcm_read:1692: read error: Input/output error

dmesg | tail
[ 2183.810982] ALSA sound/usb/pcm.c:226: setting usb interface 2:4
[ 2183.810992] ALSA sound/usb/clock.c:216: 3:2:4: endpoint lacks sample rate attribute bit, cannot set.
[ 2283.808023] ALSA sound/core/pcm_lib.c:1752: capture write error (DMA or IRQ trouble?)

Hardware:
ASUS AT5IONT-I (Atom D525 w/NVIDIA ION2)
Logitech, Inc. QuickCam Pro 4000 (ID 046d:08b2)

I also have a Logitech QuickCam web but it shows the same capture write error in dmesg

Wish I knew what knobs could affect DMA/IRQ ...

cat /proc/dma
4: cascade

cat /proc/interrupts
CPU0
0: 38 XT-PIC-XT timer
1: 2 XT-PIC-XT i8042
2: 0 XT-PIC-XT cascade
8: 1 XT-PIC-XT rtc0
9: 0 XT-PIC-XT acpi
10: 74 XT-PIC-XT uhci_hcd:usb3, xhci_hcd:usb6, saa7164[0]
11: 34047 XT-PIC-XT uhci_hcd:usb4, ahci, hda_intel, nvidia
12: 4 XT-PIC-XT i8042
14: 4 XT-PIC-XT ehci_hcd:usb1, uhci_hcd:usb2
15: 10431 XT-PIC-XT uhci_hcd:usb5, hda_intel
16: 0 PCI-MSI-edge pciehp
17: 0 PCI-MSI-edge pciehp
18: 0 PCI-MSI-edge pciehp
19: 0 PCI-MSI-edge pciehp
23: 1116 PCI-MSI-edge eth0
24: 5788 PCI-MSI-edge ahci
NMI: 0 Non-maskable interrupts
LOC: 52947 Local timer interrupts
SPU: 0 Spurious interrupts
PMI: 0 Performance monitoring interrupts
PND: 0 Performance pending work
RES: 0 Rescheduling interrupts
CAL: 0 Function call interrupts
TLB: 0 TLB shootdowns
TRM: 0 Thermal event interrupts
THR: 0 Threshold APIC interrupts
MCE: 0 Machine check exceptions
MCP: 2 Machine check polls
ERR: 0
MIS: 0

well this has been around a while here is the manual it basically say open a terminal run gnome-alsamixer and select input your mic then enable capture and also mic boost. good luck.and

1 members found this post helpful.

Thanks! Your suggestion worked. That saved me a couple sleepless nights. I was literally inspecting kernel code to see what the problem could be.

gnome-alsamixer isn't installed by default apparently. The Rec check box is what did the trick. I had been using alsamixer did not see its equivalent. Also, apparently the older webcam may be broken in hw or in kernel.

Your link enlightened me to amixer ... to do what I did in gnome-alsamixer, its
amixer -c 1 sset 'Mic' toggle.

Though, scratching my head a bit as to why google didnt give me much help on this one ... oh well, others may benefit from my ignorance now.

sudo apt-get install libv4l-0 for the old gspca cams for skype and do this. as in the skype and ubuntu manual. in a termial run . if running 64 bit UBUNTU sudo apt-get lib32v4l-0 then you also need or do as I did edited my programs even my browsers so I could use my old cam in my browser or in skype. Been doing that since the 2.6.27 kernel when we went to v4l2 .
good luck