Hi Laurent,
here the results of my tests:
MaxPayloadTransferSize Value Returned from device
Result
0 128
uvcvideo: USB isochronous frame lost (-71).
1 128
uvcvideo: USB isochronous frame lost (-71).
42 128
uvcvideo: USB isochronous frame lost (-71).
1024 1024
works right with few USB iso frame lost
0xFFFF 3072
no error but also no capture :-(
My conclusion is that MaxPayloadTransferSize, regardless of
specification, is not readonly... seems to be that device round this
value to the closest that is supported (see also my lsusb in file
lsusb.txt).
I think that the right bandwidth allocation must be calculated in
the driver and set up in the device (the same you have done for
frameinterval value :-).
BR Simone.
Laurent Pinchart wrote:
Hi Simone,
On Tuesday 03 February 2009, Simone Freddio wrote:
Hi Jan, hi Laurent...
i have the same problem with different webcam... i think to have
found the problem, Laurent tell me if i am wrong, i'll go to explain:
The problem is in the bandwidth, the uvcdriver ALWAYS ask to usb
layer a dw_MaxPayloadTransferSize that is fetched only when the device
is opening;
In my case is always set to 3072 (3x1024). I have tried changing
uvc_video.c in a very dirty manner (excuse me Laurent)
Don't worry :-)
in this way:
In function 'uvc_set_video_ctrl' where there is:
put_unaligned_le32(ctrl->dwMaxVideoFrameSize, &data[18]);
put_unaligned_le32(ctrl->dwMaxPayloadTransferSize, &data[22]);
i have commented out the second line and changed it in:
put_unaligned_le32(1024, &data[22]);
In this way i have always force uvc driver to ask for a payload size
of 1024.
According to the UVC 1.1 specification, the dwMaxPayloadTransferSize is set by
the device and read only from the host. The value set by the host shouldn't
matter.
After recompiling, reinstalling, unload e load the module, i can get
two webcam working fine and simultaneously.
Now i didn't have a big experience and i can't change source myself
in the right way... but i think that my observation can be usefull.
It is, thanks.
I think that the best way to re-negotiate the bandwidth is to set
video streaming parameters (framesize and frameinterval) and after ask
the device wich bandwidth it requests.
That's exactly what the driver does. In uvc_probe_video, each SET_CUR request
is followed by a GET_CUR to retrieve the bandwidth requested by the camera.
In a short way, at the end of uvc_set_video_ctrl function a call to
uvc_get_video_ctrl will solve the problem... what do you think Laurent?)
This is already handled by uvc_probe_video. From your report it seems that the
device doesn't touch the dwMaxPayloadTransferSize at all and just returns the
value sets by the host.
Could you (or Jan) try to set dwMaxPayloadTransferSize to a weird value (let's
say 42) and see what the device returns in the next GET_CUR call ?
Best regards,
Laurent Pinchart
Bus 001 Device 005: ID 0ac8:332d Z-Star Microelectronics Corp.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2 ?
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 64
idVendor 0x0ac8 Z-Star Microelectronics Corp.
idProduct 0x332d
bcdDevice 1.00
iManufacturer 1 Vimicro Corp.
iProduct 2 Vega USB 2.0 Camera.
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 581
bNumInterfaces 2
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 500mA
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 0
bInterfaceCount 2
bFunctionClass 14 Video
bFunctionSubClass 3 Video Interface Collection
bFunctionProtocol 0
iFunction 2 Vega USB 2.0 Camera.
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 1 Video Control
bInterfaceProtocol 0
iInterface 2 Vega USB 2.0 Camera.
VideoControl Interface Descriptor:
bLength 13
bDescriptorType 36
bDescriptorSubtype 1 (HEADER)
bcdUVC 1.00
wTotalLength 79
dwClockFrequency 24.000000MHz
bInCollection 1
baInterfaceNr( 0) 1
VideoControl Interface Descriptor:
bLength 18
bDescriptorType 36
bDescriptorSubtype 2 (INPUT_TERMINAL)
bTerminalID 1
wTerminalType 0x0201 Camera Sensor
bAssocTerminal 0
iTerminal 0
wObjectiveFocalLengthMin 0
wObjectiveFocalLengthMax 0
wOcularFocalLength 0
bControlSize 3
bmControls 0x0004000a
Auto-Exposure Mode
Exposure Time (Absolute)
Privacy
VideoControl Interface Descriptor:
bLength 11
bDescriptorType 36
bDescriptorSubtype 5 (PROCESSING_UNIT)
Warning: Descriptor too short
bUnitID 2
bSourceID 1
wMaxMultiplier 0
bControlSize 2
bmControls 0x0000177f
Brightness
Contrast
Hue
Saturation
Sharpness
Gamma
White Balance Temperature
Backlight Compensation
Gain
Power Line Frequency
White Balance Temperature, Auto
iProcessing 0
bmVideoStandards 0x 9
None
SECAM - 625/50
VideoControl Interface Descriptor:
bLength 9
bDescriptorType 36
bDescriptorSubtype 3 (OUTPUT_TERMINAL)
bTerminalID 3
wTerminalType 0x0101 USB Streaming
bAssocTerminal 0
bSourceID 2
iTerminal 0
VideoControl Interface Descriptor:
bLength 28
bDescriptorType 36
bDescriptorSubtype 6 (EXTENSION_UNIT)
bUnitID 4
guidExtensionCode {5dc717a9-1941-da11-ae0e-000d56ac7b4c}
bNumControl 13
bNrPins 1
baSourceID( 0) 1
bControlSize 3
bmControls( 0) 0xf9
bmControls( 1) 0x1f
bmControls( 2) 0x18
iExtension 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x000a 1x 10 bytes
bInterval 5
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
VideoStreaming Interface Descriptor:
bLength 14
bDescriptorType 36
bDescriptorSubtype 1 (INPUT_HEADER)
bNumFormats 1
wTotalLength 343
bEndPointAddress 130
bmInfo 0
bTerminalLink 3
bStillCaptureMethod 2
bTriggerSupport 1
bTriggerUsage 1
bControlSize 1
bmaControls( 0) 27
VideoStreaming Interface Descriptor:
bLength 27
bDescriptorType 36
bDescriptorSubtype 4 (FORMAT_UNCOMPRESSED)
bFormatIndex 1
bNumFrameDescriptors 5
guidFormat
{59555932-0000-1000-8000-00aa00389b71}
bBitsPerPixel 16
bDefaultFrameIndex 1
bAspectRatioX 0
bAspectRatioY 0
bmInterlaceFlags 0x00
Interlaced stream or variable: No
Fields per frame: 1 fields
Field 1 first: No
Field pattern: Field 1 only
bCopyProtect 0
VideoStreaming Interface Descriptor:
bLength 54
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 1
bmCapabilities 0x00
Still image unsupported
wWidth 640
wHeight 480
dwMinBitRate 24576000
dwMaxBitRate 147456000
dwMaxVideoFrameBufferSize 614400
dwDefaultFrameInterval 333333
bFrameIntervalType 7
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666667
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 1333333
dwFrameInterval( 6) 2000000
VideoStreaming Interface Descriptor:
bLength 54
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 2
bmCapabilities 0x00
Still image unsupported
wWidth 352
wHeight 288
dwMinBitRate 24576000
dwMaxBitRate 147456000
dwMaxVideoFrameBufferSize 202752
dwDefaultFrameInterval 333333
bFrameIntervalType 7
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666667
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 1333333
dwFrameInterval( 6) 2000000
VideoStreaming Interface Descriptor:
bLength 54
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 3
bmCapabilities 0x00
Still image unsupported
wWidth 320
wHeight 240
dwMinBitRate 24576000
dwMaxBitRate 147456000
dwMaxVideoFrameBufferSize 153600
dwDefaultFrameInterval 333333
bFrameIntervalType 7
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666667
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 1333333
dwFrameInterval( 6) 2000000
VideoStreaming Interface Descriptor:
bLength 54
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 4
bmCapabilities 0x00
Still image unsupported
wWidth 176
wHeight 144
dwMinBitRate 24576000
dwMaxBitRate 147456000
dwMaxVideoFrameBufferSize 50688
dwDefaultFrameInterval 333333
bFrameIntervalType 7
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666667
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 1333333
dwFrameInterval( 6) 2000000
VideoStreaming Interface Descriptor:
bLength 54
bDescriptorType 36
bDescriptorSubtype 5 (FRAME_UNCOMPRESSED)
bFrameIndex 5
bmCapabilities 0x00
Still image unsupported
wWidth 160
wHeight 120
dwMinBitRate 24576000
dwMaxBitRate 147456000
dwMaxVideoFrameBufferSize 38400
dwDefaultFrameInterval 333333
bFrameIntervalType 7
dwFrameInterval( 0) 333333
dwFrameInterval( 1) 400000
dwFrameInterval( 2) 500000
dwFrameInterval( 3) 666667
dwFrameInterval( 4) 1000000
dwFrameInterval( 5) 1333333
dwFrameInterval( 6) 2000000
VideoStreaming Interface Descriptor:
bLength 26
bDescriptorType 36
bDescriptorSubtype 3 (STILL_IMAGE_FRAME)
bEndpointAddress 0
bNumImageSizePatterns 5
wWidth( 0) 640
wHeight( 0) 480
wWidth( 1) 352
wHeight( 1) 288
wWidth( 2) 320
wHeight( 2) 240
wWidth( 3) 176
wHeight( 3) 144
wWidth( 4) 160
wHeight( 4) 120
bNumCompressionPatterns 5
VideoStreaming Interface Descriptor:
bLength 6
bDescriptorType 36
bDescriptorSubtype 13 (COLORFORMAT)
bColorPrimaries 0 (Unspecified)
bTransferCharacteristics 0 (Unspecified)
bMatrixCoefficients 0 (Unspecified)
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 1
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0080 1x 128 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 2
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 3
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0400 1x 1024 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 4
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0b00 2x 768 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 5
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x0c00 2x 1024 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 6
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x1380 3x 896 bytes
bInterval 1
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 7
bNumEndpoints 1
bInterfaceClass 14 Video
bInterfaceSubClass 2 Video Streaming
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 5
Transfer Type Isochronous
Synch Type Asynchronous
Usage Type Data
wMaxPacketSize 0x1400 3x 1024 bytes
bInterval 1
Device Qualifier (for other device speed):
bLength 10
bDescriptorType 6
bcdUSB 2.00
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2 ?
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 64
bNumConfigurations 1
Device Status: 0x0000
(Bus Powered)
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 9 Hub
bDeviceSubClass 0 Unused
bDeviceProtocol 0 Full speed (or root) hub
bMaxPacketSize0 64
idVendor 0x1d6b Linux Foundation
idProduct 0x0002 2.0 root hub
bcdDevice 2.06
iManufacturer 3 Linux 2.6.27-9-generic ehci_hcd
iProduct 2 EHCI Host Controller
iSerial 1 0000:00:1d.7
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 Full speed (or root) hub
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 11
bDescriptorType 41
nNbrPorts 8
wHubCharacteristic 0x000a
No power switching (usb 1.0)
Per-port overcurrent protection
bPwrOn2PwrGood 10 * 2 milli seconds
bHubContrCurrent 0 milli Ampere
DeviceRemovable 0x00 0x00
PortPwrCtrlMask 0xff 0xff
Hub Port Status:
Port 1: 0000.0503 highspeed power enable connect
Port 2: 0000.0503 highspeed power enable connect
Port 3: 0000.0100 power
Port 4: 0000.0100 power
Port 5: 0000.0100 power
Port 6: 0000.0100 power
Port 7: 0000.0100 power
Port 8: 0000.0100 power
Device Status: 0x0003
Self Powered
Remote Wakeup Enabled
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