Re: [alsa-devel] bandwidth issue with usb-audio in alsa

28 May 2008


      Hi Clemens/Jon,
I tried to understand the "lsusb -v" and started scanning through it.
After a few scan I realized that Bus-001 where I have connected my device
is a FS bus. The Bus-002 is HS. So, I moved my device to Bus-002. It all
works without any Bandwidth issues.
Thanks a lot for guiding me in to the right direction.
Can some one also suggest, why is there a problem with oss-emulation on
my system. I am using OSS-emulation API. As I mentioned earlier, I have a
sound card "card0" on my system which is mapped to /dev/dsp and I am able
to playback any data on this. As soon as I connect a USB-Audio device
(which reflects as Card1 in /proc/asound and new nodes /dev/dsp1
/dev/mixer1 etc created), I can no longer use the Card0. The /dev/dsp tries
to open a USB-Audio type devices (which should actually happen when I try
to open the /dev/dsp1). I think there is some dynamic remapping which
happens, and I am unable to trace it.
Regards,
Kunal
....
Hi Clemens,
I have copied the "lsusb -v" output below (end of this e-mail). The
"HUB" and the "iPod" are connected to Bus-001. Bus-002 is not being used.
As I can see from the Log, BUS-001 and BUS-002 both have usb (root ?)
hubs with single TT. Each of these buses have only one port available. So,
I guess that single "TT" should not be a problem. Am I right?
The Belking hub which I have connected to "Bus-001" has "TT" per
port. It also says "bInterval" equal to 255.
The iPod device which I am using has two configurations. I am using
the second configuration. Second configuration again has two interfaces.
Second (HID Class) interface is being used and works fine. Problem is with
the the first interface (with altsetting==1), which is an
audio-streaming-class.
The parameters for this interface are: (copied from the log below)
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x00c0  1x 192 bytes
        bInterval               1
        bRefresh                0
        bSynchAddress           0
        AudioControl Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x01
            Sampling Frequency
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
Here "bInterval" is "1" and the transactions are not getting
scheduled at this desired speed.
Regards,
Kunal
Bus 002 Device 001: ID 0000:0000  
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 Unused
  bDeviceProtocol         1 Single TT
  bMaxPacketSize0        64
  idVendor           0x0000 
  idProduct          0x0000 
  bcdDevice            2.06
  iManufacturer           3 Linux 2.6.22.6 ehci_hcd
  iProduct                2 Freescale On-Chip EHCI Host Controller
  iSerial                 1 fsl-ehci.1
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           25
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval              12
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             1
  wHubCharacteristic 0x0009
    Per-port power switching
    Per-port overcurrent protection
    TT think time 8 FS bits
  bPwrOn2PwrGood       10 * 2 milli seconds
  bHubContrCurrent      0 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0x00 
 Hub Port Status:
   Port 1: 0000.0100 power
Bus 001 Device 008: ID 05ac:1262 Apple Computer, Inc. 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x05ac Apple Computer, Inc.
  idProduct          0x1262 
  bcdDevice            0.01
  iManufacturer           1 Apple Inc.
  iProduct                2 iPod
  iSerial                 3 000A27001A2E8B0C
  bNumConfigurations      2
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           32
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xc0
      Self Powered
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         8 Mass Storage
      bInterfaceSubClass      6 SCSI
      bInterfaceProtocol     80 Bulk (Zip)
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength          149
    bNumInterfaces          3
    bConfigurationValue     2
    iConfiguration          4 iPod USB Interface
    bmAttributes         0xc0
      Self Powered
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      1 Control Device
      bInterfaceProtocol      0 
      iInterface              0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdADC               1.00
        wTotalLength           30
        bInCollection           1
        baInterfaceNr( 0)       1
      AudioControl Interface Descriptor:
        bLength                12
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0201 Microphone
        bAssocTerminal          2
        bNrChannels             2
        wChannelConfig     0x0003
          Left Front (L)
          Right Front (R)
        iChannelNames           0 
        iTerminal               0 
      AudioControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             2
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          1
        bSourceID               1
        iTerminal               0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass         1 Audio
      bInterfaceSubClass      2 Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      AudioStreaming Interface Descriptor:
        bLength                 7
        bDescriptorType        36
        bDescriptorSubtype      1 (AS_GENERAL)
        bTerminalLink           2
        bDelay                  1 frames
        wFormatTag              1 PCM
      AudioStreaming Interface Descriptor:
        bLength                35
        bDescriptorType        36
        bDescriptorSubtype      2 (FORMAT_TYPE)
        bFormatType             1 (FORMAT_TYPE_I)
        bNrChannels             2
        bSubframeSize           2
        bBitResolution         16
        bSamFreqType            9 Discrete
        tSamFreq[ 0]         8000
        tSamFreq[ 1]        11025
        tSamFreq[ 2]        12000
        tSamFreq[ 3]        16000
        tSamFreq[ 4]        22050
        tSamFreq[ 5]        24000
        tSamFreq[ 6]        32000
        tSamFreq[ 7]        44100
        tSamFreq[ 8]        48000
      Endpoint Descriptor:
        bLength                 9
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            1
          Transfer Type            Isochronous
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x00c0  1x 192 bytes
        bInterval               1
        bRefresh                0
        bSynchAddress           0
        AudioControl Endpoint Descriptor:
          bLength                 7
          bDescriptorType        37
          bDescriptorSubtype      1 (EP_GENERAL)
          bmAttributes         0x01
            Sampling Frequency
          bLockDelayUnits         0 Undefined
          wLockDelay              0 Undefined
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Devices
      bInterfaceSubClass      0 No Subclass
      bInterfaceProtocol      0 None
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.01
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength      96
         Report Descriptors: 
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  bNumConfigurations      2
Bus 001 Device 006: ID 050d:0234 Belkin Components F5U234 USB 2.0 4-Port Hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 Unused
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x050d Belkin Components
  idProduct          0x0234 F5U234 USB 2.0 4-Port Hub
  bcdDevice            0.00
  iManufacturer           0 
  iProduct                0 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           25
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                2mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0001  1x 1 bytes
        bInterval             255
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             4
  wHubCharacteristic 0x0000
    Ganged power switching
    Ganged overcurrent protection
  bPwrOn2PwrGood       50 * 2 milli seconds
  bHubContrCurrent      1 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0x00 
 Hub Port Status:
   Port 1: 0000.0103 power enable connect
   Port 2: 0000.0100 power
   Port 3: 0000.0100 power
   Port 4: 0000.0100 power
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 Unused
  bDeviceProtocol         2 TT per port
  bMaxPacketSize0        64
  bNumConfigurations      1
Bus 001 Device 001: ID 0000:0000  
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 Unused
  bDeviceProtocol         1 Single TT
  bMaxPacketSize0        64
  idVendor           0x0000 
  idProduct          0x0000 
  bcdDevice            2.06
  iManufacturer           3 Linux 2.6.22.6 ehci_hcd
  iProduct                2 Freescale On-Chip EHCI Host Controller
  iSerial                 1 fsl-ehci.0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           25
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval              12
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             1
  wHubCharacteristic 0x0009
    Per-port power switching
    Per-port overcurrent protection
    TT think time 8 FS bits
  bPwrOn2PwrGood       10 * 2 milli seconds
  bHubContrCurrent      0 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0x00 
 Hub Port Status:
   Port 1: 0000.0103 power enable connect
Clemens Ladisch wrote:
...
Kunal Singh wrote:
...
I have some update on the issue which I had reported earlier. In my

last e-mail, I had not mentioned that iPod is connected to the target
through a USB (HS) Hub. When I connect the
...
...
same hub to my Desktop and read its configuration using "usbview" - I
see that "interval" for this hub is mentioned
...
...
as "256 msec". (I have two hubs and I get all the results same with both
the hubs).
...
...
Please show the output of "lsusb -v".
Regards,
Clemens
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