> What kernel version are you using? > I am using kernel version 2.6.25.I cann't use current linux kernel version because it uses the generic write function and for my application I need pl2303_write. I am writing a driver through which I can communicate to various MCM devices connected in parallel using RS-485. I am now able to separate Adddress byte and data bytes, driver is able to write the addr byte properly as well as driver is able to copy the data bytes in write_urb->transfer_buffer. But when I tried to submit the write_urb->transfer_buffer with data bytes, kernel log messages show the following error. drivers/usb/serial/usb-serial.c: USB Serial support registered for pl2303_mcm pl2303_mcm 7-1:1.0: pl2303_mcm converter detected /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: device type: 2 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0xc0:0x1:0x8484:0x0 1 - 2 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0x40:0x1:0x404:0x0 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0xc0:0x1:0x8484:0x0 1 - 2 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0xc0:0x1:0x8383:0x0 1 - 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0xc0:0x1:0x8484:0x0 1 - 2 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0x40:0x1:0x404:0x1 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0xc0:0x1:0x8484:0x0 1 - 2 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0xc0:0x1:0x8383:0x0 1 - 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0x40:0x1:0x0:0x1 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0x40:0x1:0x1:0x0 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: 0x40:0x1:0x2:0x44 0 usb 7-1: pl2303_mcm converter now attached to ttyUSB0 usbcore: registered new interface driver pl2303_mcm /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: Prolific PL2303 USB to serial adaptor driver modified for MCM communication [teleset@telab2 ~]$ dmesg | tail -100 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: pl2303_write_bulk_callback - port 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: set_control_lines - value = 0, retval = 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: pl2303_write_room - port 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: pl2303_write_room - returns 199 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: We got the length of USer buffer 8 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: set_control_lines - value = 3, retval = 0 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: We successfully copied the user buffer into Buf_Addr /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: We successfully copied the user buffer into write_urb->transfer_buffer pl2303_mcm ttyUSB0: pl2303_write - length = 1, data = 02 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: We successfully submited the write_URB Data in The Data BUF 0 is -----> 08 Data in The Data BUF 1 is -----> 00 Data in The Data BUF 2 is -----> 00 Data in The Data BUF 3 is -----> 00 Data in The Data BUF 4 is -----> 00 Data in The Data BUF 5 is -----> 00 Data in The Data BUF 6 is -----> 00 Data in The Data BUF 7 is -----> f8 Data in The C BUF 0 is -----> 08 Data in The C BUF 1 is -----> 00 Data in The C BUF 2 is -----> 00 Data in The C BUF 3 is -----> 00 Data in The C BUF 4 is -----> 00 Data in The C BUF 5 is -----> 00 Data in The C BUF 6 is -----> 00 Data in The C BUF 7 is -----> f8 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: We successfully copied the C buffer into write_urb->transfer_buffer pl2303_mcm ttyUSB0: pl2303_write - length = 8, data = 08 00 00 00 00 00 00 f8 pl2303_mcm ttyUSB0: pl2303_write - failed submitting write urb, error -22 /home/teleset/Desktop/USB-Serial/pl2303_mcm.c: pl2303_write_bulk_callback - port 0 thanks- Raj. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
