LibUSB driver issues: timeout

问题

I am attempting to write a linux driver for a printer. I have run USBSnoop on windows XP and obtained the log. In this log it sets wMaxPacketSize to 1026. After i set the interface i get the response of 75 bytes. If i set it to 64 (in the lsusb output) i obviously only get 64 bytes back.

My issue is on a bulk transfer to/from the device i get timeouts. I think i have the same problem as here: http://libusb.6.n5.nabble.com/libusb-bulk-transfer-return-timeout-error-and-transferred-set-to-0-td5712761.html

I performed the libusb_clear_halt() and i get a similar result to the linked post above. Down the bottom of it says "split buffer into 64 bytes manually" to solve it. My question is how to split the packets? This is my first time using LibUSB.

Here is the output of lsusb -v

Bus 002 Device 009: ID 07ce:c000  
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            7 Printer
  bDeviceSubClass         1 Printer
  bDeviceProtocol         2 Bidirectional
  bMaxPacketSize0        64
  idVendor           0x07ce 
  idProduct          0xc000 
  bcdDevice            1.00
  iManufacturer           1 COPAL
  iProduct                2 COPAL USB Printer
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           32
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xc0
      Self Powered
    MaxPower              200mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         7 Printer
      bInterfaceSubClass      1 Printer
      bInterfaceProtocol      2 Bidirectional
      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     0x0040  1x 64 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               0.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         0
  bNumConfigurations      0
Device Status:     0x0001
  Self Powered

Edit: this was in the dmesg

usb 2-1.1: new high-speed USB device number 9 using ehci_hcd
usb 2-1.1: config 1 interface 0 altsetting 0 bulk endpoint 0x1 has invalid maxpacket 64
usb 2-1.1: config 1 interface 0 altsetting 0 bulk endpoint 0x82 has invalid maxpacket 64

Edit: I think it may be that linux is getting in the way. On wireshark and i can see the packets come back correctly but not calling my callback function. I already removed the usblp driver. Any ideas?

回答1:

Got a similar problem. Haven't figured out why I get the timeout errors, yet. Though it seems like they occur much more often for larger package sizes. If you want to split your package, just write yourself a function that splits your large buffer[1024] into packages of 64 bytes, then do a loop that always takes the next 64 bytes from the buffer, puts it in a small_buffer[64] and sends them via usb.

来源：https://stackoverflow.com/questions/27139854/libusb-driver-issues-timeout