안녕하세요. 개발업무를 진행하는중 발생된 문제에 대한 의견을 듣고자 올립니다.

삼성 S5PC100 프로세서를 사용하고 USB 1port를 내장한 임베디드보드를 사용하고 있습니다.
USB 1 port에 USB-to-Serial Cable을 이용하여 UART 데이터를 수신하는 것은 잘 됩니다.
문제는 추가적인 USB 디바이스를 붙이기 위해 USB hub를 사용하게 되었는데요.
USB 허브는 인식을 하였습니다만, USB-to-Serial Adapter를 연결하면 아래와 같은 에러메시지가 출력됩니다.

리눅스 커널 버전은 2.6.29를 사용하고 있습니다.

고수님들의 많은 의견 부탁드립니다.

hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
hub 1-0:1.0: port 1, status 0101, change 0001, 12 Mb/s
hub 1-0:1.0: debounce: port 1: total 100ms stable 100ms status 0x101
usb 1-1: new high speed USB device using s3c_otghcd and address 2
usb 1-1: default language 0x0409
usb 1-1: New USB device found, idVendor=05e3, idProduct=0606
usb 1-1: New USB device strings: Mfr=0, Product=1, SerialNumber=0
usb 1-1: Product: USB2.0 Hub
usb 1-1: uevent
usb 1-1: usb_probe_device
usb 1-1: configuration #1 chosen from 1 choice
usb 1-1: adding 1-1:1.0 (config #1, interface 0)
usb 1-1:1.0: uevent
hub 1-1:1.0: usb_probe_interface
hub 1-1:1.0: usb_probe_interface - got id
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 4 ports detected
hub 1-1:1.0: standalone hub
hub 1-1:1.0: individual port power switching
hub 1-1:1.0: individual port over-current protection
hub 1-1:1.0: Single TT
hub 1-1:1.0: TT requires at most 32 FS bit times (2664 ns)
hub 1-1:1.0: Port indicators are supported
hub 1-1:1.0: power on to power good time: 100ms
hub 1-1:1.0: local power source is good
hub 1-1:1.0: enabling power on all ports
drivers/usb/core/inode.c: creating file '002'
hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
hub 1-0:1.0: port 1 enable change, status 00000503
hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0000
hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0010
hub 1-1:1.0: port 4, status 0101, change 0001, 12 Mb/s
hub 1-1:1.0: debounce: port 4: total 100ms stable 100ms status 0x101
usb 1-1.4: new full speed USB device using s3c_otghcd and address 3
usb 1-1.4: device descriptor read/64, error -71
usb 1-1.4: device descriptor read/64, error -71
usb 1-1.4: new full speed USB device using s3c_otghcd and address 4
usb 1-1.4: device descriptor read/64, error -71
usb 1-1.4: device descriptor read/64, error -71
usb 1-1.4: new full speed USB device using s3c_otghcd and address 5
usb 1-1.4: device not accepting address 5, error -71
usb 1-1.4: new full speed USB device using s3c_otghcd and address 6
usb 1-1.4: device not accepting address 6, error -71
hub 1-1:1.0: unable to enumerate USB device on port 4
hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0010
hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
hub 1-0:1.0: port 1, status 0000, change 0003, 12 Mb/s
usb 1-1: USB disconnect, address 2
usb 1-1: unregistering device
usb 1-1: usb_disable_device nuking all URBs
usb 1-1: unregistering interface 1-1:1.0

커널옵션은 다음과 같습니다.

#
# USB Input Devices
#
CONFIG_USB_HID=y
# CONFIG_HID_PID is not set
# CONFIG_USB_HIDDEV is not set

#
# Special HID drivers
#
CONFIG_HID_COMPAT=y
CONFIG_HID_A4TECH=y
CONFIG_HID_APPLE=y
CONFIG_HID_BELKIN=y
CONFIG_HID_CHERRY=y
CONFIG_HID_CHICONY=y
CONFIG_HID_CYPRESS=y
CONFIG_HID_EZKEY=y
CONFIG_HID_GYRATION=y
CONFIG_HID_LOGITECH=y
# CONFIG_LOGITECH_FF is not set
# CONFIG_LOGIRUMBLEPAD2_FF is not set
CONFIG_HID_MICROSOFT=y
CONFIG_HID_MONTEREY=y
CONFIG_HID_NTRIG=y
CONFIG_HID_PANTHERLORD=y
# CONFIG_PANTHERLORD_FF is not set
CONFIG_HID_PETALYNX=y
CONFIG_HID_SAMSUNG=y
CONFIG_HID_SONY=y
CONFIG_HID_SUNPLUS=y
# CONFIG_GREENASIA_FF is not set
CONFIG_HID_TOPSEED=y
# CONFIG_THRUSTMASTER_FF is not set
# CONFIG_ZEROPLUS_FF is not set
CONFIG_USB_SUPPORT=y
CONFIG_USB_ARCH_HAS_HCD=y
CONFIG_USB_ARCH_HAS_OHCI=y
# CONFIG_USB_ARCH_HAS_EHCI is not set
CONFIG_USB=y
CONFIG_USB_DEBUG=y
CONFIG_USB_ANNOUNCE_NEW_DEVICES=y

#
# Miscellaneous USB options
#
CONFIG_USB_DEVICEFS=y
# CONFIG_USB_DEVICE_CLASS is not set
# CONFIG_USB_DYNAMIC_MINORS is not set
# CONFIG_USB_OTG is not set
# CONFIG_USB_MON is not set
# CONFIG_USB_WUSB is not set
# CONFIG_USB_WUSB_CBAF is not set

#
# USB Host Controller Drivers
#
# CONFIG_USB_C67X00_HCD is not set
# CONFIG_USB_OXU210HP_HCD is not set
# CONFIG_USB_ISP116X_HCD is not set
# CONFIG_USB_OHCI_HCD is not set
# CONFIG_USB_SL811_HCD is not set
# CONFIG_USB_R8A66597_HCD is not set
# CONFIG_USB_HWA_HCD is not set
CONFIG_USB_S3C_OTG_HOST=y
# CONFIG_USB_MUSB_HDRC is not set

#
# USB Device Class drivers
#
# CONFIG_USB_ACM is not set
# CONFIG_USB_PRINTER is not set
# CONFIG_USB_WDM is not set
# CONFIG_USB_TMC is not set

#
# NOTE: USB_STORAGE depends on SCSI but BLK_DEV_SD may also be needed;
#

#
# see USB_STORAGE Help for more information
#
CONFIG_USB_STORAGE=y
# CONFIG_USB_STORAGE_DEBUG is not set
# CONFIG_USB_STORAGE_DATAFAB is not set
# CONFIG_USB_STORAGE_FREECOM is not set
# CONFIG_USB_STORAGE_ISD200 is not set
# CONFIG_USB_STORAGE_USBAT is not set
# CONFIG_USB_STORAGE_SDDR09 is not set
# CONFIG_USB_STORAGE_SDDR55 is not set
# CONFIG_USB_STORAGE_JUMPSHOT is not set
# CONFIG_USB_STORAGE_ALAUDA is not set
# CONFIG_USB_STORAGE_ONETOUCH is not set
# CONFIG_USB_STORAGE_KARMA is not set
# CONFIG_USB_STORAGE_CYPRESS_ATACB is not set
# CONFIG_USB_LIBUSUAL is not set

#
# USB Imaging devices
#
# CONFIG_USB_MDC800 is not set
# CONFIG_USB_MICROTEK is not set

#
# USB port drivers
#
CONFIG_USB_SERIAL=y
CONFIG_USB_SERIAL_CONSOLE=y
# CONFIG_USB_EZUSB is not set
CONFIG_USB_SERIAL_GENERIC=y
# CONFIG_USB_SERIAL_AIRCABLE is not set
# CONFIG_USB_SERIAL_ARK3116 is not set
# CONFIG_USB_SERIAL_BELKIN is not set
# CONFIG_USB_SERIAL_CH341 is not set
# CONFIG_USB_SERIAL_WHITEHEAT is not set
# CONFIG_USB_SERIAL_DIGI_ACCELEPORT is not set
# CONFIG_USB_SERIAL_CP2101 is not set
# CONFIG_USB_SERIAL_CYPRESS_M8 is not set
# CONFIG_USB_SERIAL_EMPEG is not set
CONFIG_USB_SERIAL_FTDI_SIO=y
# CONFIG_USB_SERIAL_FUNSOFT is not set
# CONFIG_USB_SERIAL_VISOR is not set
# CONFIG_USB_SERIAL_IPAQ is not set
# CONFIG_USB_SERIAL_IR is not set
# CONFIG_USB_SERIAL_EDGEPORT is not set
# CONFIG_USB_SERIAL_EDGEPORT_TI is not set
# CONFIG_USB_SERIAL_GARMIN is not set
# CONFIG_USB_SERIAL_IPW is not set
# CONFIG_USB_SERIAL_IUU is not set
# CONFIG_USB_SERIAL_KEYSPAN_PDA is not set
# CONFIG_USB_SERIAL_KEYSPAN is not set
# CONFIG_USB_SERIAL_KLSI is not set
# CONFIG_USB_SERIAL_KOBIL_SCT is not set
# CONFIG_USB_SERIAL_MCT_U232 is not set
# CONFIG_USB_SERIAL_MOS7720 is not set
# CONFIG_USB_SERIAL_MOS7840 is not set
# CONFIG_USB_SERIAL_MOTOROLA is not set
# CONFIG_USB_SERIAL_NAVMAN is not set
CONFIG_USB_SERIAL_PL2303=y
# CONFIG_USB_SERIAL_OTI6858 is not set
# CONFIG_USB_SERIAL_SPCP8X5 is not set
# CONFIG_USB_SERIAL_HP4X is not set
# CONFIG_USB_SERIAL_SAFE is not set
# CONFIG_USB_SERIAL_SIEMENS_MPI is not set
# CONFIG_USB_SERIAL_SIERRAWIRELESS is not set
# CONFIG_USB_SERIAL_TI is not set
# CONFIG_USB_SERIAL_CYBERJACK is not set
# CONFIG_USB_SERIAL_XIRCOM is not set
CONFIG_USB_SERIAL_OPTION=y
# CONFIG_USB_SERIAL_OMNINET is not set
# CONFIG_USB_SERIAL_OPTICON is not set
# CONFIG_USB_SERIAL_DEBUG is not set