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I'm thinking about writing a driver for a usb video capture card, but I've run into a strange problem early on. When I plug the card into windows and use ...
- 01-04-2010 #1Just Joined!
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- Jan 2010
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OS differences in USB endpoints?
I'm thinking about writing a driver for a usb video capture card, but I've run into a strange problem early on. When I plug the card into windows and use UsbSnoop to record usb bus messages passed to the card from windows and the driver, I see this (in part):
Using a program like usbview, it looks like there is one configuration (1) with one interface (0), with four alternate settings. Each alternate setting has the endpoints shown above, 1 in/out and 2 out.Code:ConfigurationDescriptor = 0x897662c0 (configure) ConfigurationDescriptor : bLength = 9 ConfigurationDescriptor : bDescriptorType = 0x00000002 ConfigurationDescriptor : wTotalLength = 0x000000bd ConfigurationDescriptor : bNumInterfaces = 0x00000001 ConfigurationDescriptor : bConfigurationValue = 0x00000001 ConfigurationDescriptor : iConfiguration = 0x00000000 ConfigurationDescriptor : bmAttributes = 0x00000080 ConfigurationDescriptor : MaxPower = 0x000000fa ConfigurationHandle = 0x88fd3568 Interface[0]: Length = 76 Interface[0]: InterfaceNumber = 0 Interface[0]: AlternateSetting = 0 Interface[0]: Class = 0x000000ff Interface[0]: SubClass = 0x00000001 Interface[0]: Protocol = 0x00000001 Interface[0]: InterfaceHandle = 0x88da6f80 Interface[0]: NumberOfPipes = 3 Interface[0]: Pipes[0] : MaximumPacketSize = 0x00000200 Interface[0]: Pipes[0] : EndpointAddress = 0x00000081 Interface[0]: Pipes[0] : Interval = 0x00000000 Interface[0]: Pipes[0] : PipeType = 0x00000002 (UsbdPipeTypeBulk) Interface[0]: Pipes[0] : PipeHandle = 0x88da6f9c Interface[0]: Pipes[0] : MaxTransferSize = 0x0000ffff Interface[0]: Pipes[0] : PipeFlags = 0x00000000 Interface[0]: Pipes[1] : MaximumPacketSize = 0x00000200 Interface[0]: Pipes[1] : EndpointAddress = 0x00000001 Interface[0]: Pipes[1] : Interval = 0x00000000 Interface[0]: Pipes[1] : PipeType = 0x00000002 (UsbdPipeTypeBulk) Interface[0]: Pipes[1] : PipeHandle = 0x88da6fbc Interface[0]: Pipes[1] : MaxTransferSize = 0x0000ffff Interface[0]: Pipes[1] : PipeFlags = 0x00000000 Interface[0]: Pipes[2] : MaximumPacketSize = 0x00000200 Interface[0]: Pipes[2] : EndpointAddress = 0x00000082 Interface[0]: Pipes[2] : Interval = 0x00000000 Interface[0]: Pipes[2] : PipeType = 0x00000002 (UsbdPipeTypeBulk) Interface[0]: Pipes[2] : PipeHandle = 0x88da6fdc Interface[0]: Pipes[2] : MaxTransferSize = 0x0000ffff Interface[0]: Pipes[2] : PipeFlags = 0x00000000
Linux is a completely different story. I still see one configuration with one interface with four alternate settings, but the endpoints are different. There are no endpoints in alt setting 0, and 6 each in alt setting 1-3. Also the manufacturer and product codes are 0 in linux and non-zero under Windows. Finally, I can't bulk read/write to/from any of the endpoints under linux. I just get error 110, timeout.
I thought at first that the windows driver could be loading firmware which changes the reported endpoints, but the above UsbSnoop output was generated from the moment the device was plugged into the windows computer, and it already displays an endpoint 0x82.
Does anyone have any suggestions about what could be going on? Thanks!
Here is lsusb for the device as root:
Code:Bus 001 Device 010: ID 3100:f200 Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 255 Vendor Specific Class bDeviceSubClass 255 Vendor Specific Subclass bDeviceProtocol 255 Vendor Specific Protocol bMaxPacketSize0 64 idVendor 0x3100 idProduct 0xf200 bcdDevice 92.09 iManufacturer 0 iProduct 0 iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 171 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 100mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 0 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 255 Vendor Specific Subclass bInterfaceProtocol 255 Vendor Specific Protocol iInterface 0 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 1 bNumEndpoints 6 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 255 Vendor Specific Subclass bInterfaceProtocol 255 Vendor Specific Protocol iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 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 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x04 EP 4 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x86 EP 6 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x88 EP 8 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 2 bNumEndpoints 6 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 255 Vendor Specific Subclass bInterfaceProtocol 255 Vendor Specific Protocol iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x04 EP 4 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x86 EP 6 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x88 EP 8 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 3 bNumEndpoints 6 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 255 Vendor Specific Subclass bInterfaceProtocol 255 Vendor Specific Protocol iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x04 EP 4 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x86 EP 6 IN bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x88 EP 8 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Device Qualifier (for other device speed): bLength 10 bDescriptorType 6 bcdUSB 2.00 bDeviceClass 255 Vendor Specific Class bDeviceSubClass 255 Vendor Specific Subclass bDeviceProtocol 255 Vendor Specific Protocol bMaxPacketSize0 64 bNumConfigurations 1 Device Status: 0x0000 (Bus Powered)
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