We are developing on a small embedded device. This device us a gumstix overo board running OpenEmbedded linux. We have our development almost completely done, and have run into the strangest of bugs that we can't figure out.
We have a USB Device (Spectrophotometer) that has a USB2.0 Connection and an external power supply for the light source. Typical behavior is that you plug in the power supply, then the USB connection to a host. When the usb connection is detected by the device, the device boots up and enables the light source and fan. The device is then able to be used by the host system.
The problem is that if the device is plugged into the Gumstix before we turn on the Gumstix, the USB Device apparently is not probed by the system (and hence does not turn on). Under a normal situation, when the connection is initialized by plugging in the usb cable, the spectro turns itself on and becomes available to the system (this can be seen via "lsusb" typically). Neither of these things are happening. There is no device detected via "lsusb" and no dmesg errors of any kind that we can see. It is as if the device is not plugged in.
The device does show up and work fine if we unplug the USB cable and plug it back in once the system is booted up. It turns on and shows up on the usb bus, and we can access it with our driver.
On any other desktop or laptop, it does not matter if the host system is on or off when we plug in the spectrometer. This behavior is what I would consider to be "normal" - that the usb system is probed and initialized at boot time, and the usb devices come online. In other words, our system is fully functional as long as we plug in the usb device after the system is booted up. Unfortunately this isn't possible in our final product - everything comes on at once.
Additional Info: 1) We have tried a flash drive attached to the system when the system is turned off. Booting up the system brings the flash drive online, as expected 2) There are no messages regarding the spectro or usb device (using dmesg). "lsusb" only lists the USB hubs / controllers. It is literally as if the device is not present and not plugged in. 3) We have tried a brand new image from gumstix and an older image from last year. Both images have this problem. This problem exists on all 3 gumstix devices we use.
Does anyone have any suggestions? From what I can tell it isn't really possible to do a complete "reboot" of the usb system that is a complete emulation of "unplugging" and "replugging" a usb device. I feel like what is happening is that there is no initial probe on the usb bus that would trigger the usb handshaking, but this is somehow specific to the spectro. This seems to be a kernel issue or at least an issue in how the kernel is initializing the usb subsystem. I'm not really sure though.
I have tried the gumstix mailing list, but there doesn't seem to be anyone who has seen this issue before. Any advice or suggestions on where to start looking would be fantastic.
Thank you! Blaine
output etc. $ uname -a Linux overo 2.6.33 #1 Tue Apr 27 08:35:38 PDT 2010 armv7l GNU/Linux When the system is up and running and spectro is plugged in (working as intended), this is lsusb: Bus 001 Device 116: ID 2457:1022 Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x2457 idProduct 0x1022 bcdDevice 0.02 iManufacturer 1 USB4000 1.01.11 iProduct 2 Ocean Optics USB4000 iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 46 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 400mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 4 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 0 bInterfaceProtocol 0 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 0x82 EP 2 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 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 0x81 EP 1 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 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 bNumConfigurations 1 Device Status: 0x0000 (Bus Powered) dmesg output: usb usb1: usb auto-resume hub 1-0:1.0: hub_resume usb usb2: usb auto-resume ehci-omap ehci-omap.0: resume root hub hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0000 hub 2-0:1.0: hub_resume hub 2-0:1.0: state 7 ports 3 chg 0000 evt 0000 hub 1-0:1.0: hub_suspend usb usb1: bus auto-suspend hub 2-0:1.0: hub_suspend usb usb2: bus auto-suspend ehci-omap ehci-omap.0: suspend root hub usb usb2: usb resume ehci-omap ehci-omap.0: resume root hub hub 2-0:1.0: hub_resume ehci-omap ehci-omap.0: GetStatus port 2 status 001803 POWER sig=j CSC CONNECT hub 2-0:1.0: port 2: status 0501 change 0001 hub 2-0:1.0: state 7 ports 3 chg 0004 evt 0000 hub 2-0:1.0: port 2, status 0501, change 0000, 480 Mb/s ehci-omap ehci-omap.0: port 2 high speed ehci-omap ehci-omap.0: GetStatus port 2 status 001005 POWER sig=se0 PE CONNECT usb 2-2: new high speed USB device using ehci-omap and address 2 ehci-omap ehci-omap.0: port 2 high speed ehci-omap ehci-omap.0: GetStatus port 2 status 001005 POWER sig=se0 PE CONNECT usb 2-2: default language 0x0409 usb 2-2: udev 2, busnum 2, minor = 129 usb 2-2: New USB device found, idVendor=2457, idProduct=1022 usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0 usb 2-2: Product: Ocean Optics USB4000 usb 2-2: Manufacturer: USB4000 1.01.11 usb 2-2: uevent usb 2-2: usb_probe_device usb 2-2: configuration #1 chosen from 1 choice usb 2-2: uevent usb 2-2: adding 2-2:1.0 (config #1, interface 0) usb 2-2:1.0: uevent drivers/usb/core/inode.c: creating file '002' dmesg has nothing to say, and lusb simply lists nothing else but the two default usb controllers / hubs if we plug the device in before the system is turned on.