||<>|| = USB 2.0 Issues = When using USB 2.0 devices, some problems may be present. In older versions of Ubuntu this can be worked around by unloading the appropriate kernel module: {{{ sudo rmmod ehci_hcd }}} = Ubuntu 10.04 = Recent version of Ubuntu, and Linux in general, need only a few kernel modules to support USB mass storage devices. Everything else is handled automatically by hal and udev. When you connect a USB device you should get a message in {{{/var/log/kern.log}}} like this one: {{{ [ 5762.680031] usb 1-2: new high speed USB device using ehci_hcd and address 4 [ 5763.340703] usb 1-2: configuration #1 chosen from 1 choice }}} However, if that device is a USB storage device (flash drive) and is not found anywhere, you may have a missing module. Make sure the following modules are inserted: {{{ sudo modprobe hid sudo modprobe usbhid sudo modprobe usb_storage }}} Particularly, when {{{usb_storage}}} is inserted, you should get a message like this one: {{{ [ 712.617279] Initializing USB Mass Storage driver... [ 712.617352] usbcore: registered new interface driver usb-storage [ 712.618240] USB Mass Storage support registered. }}} Now, if you insert your flash drive again, it will be assigned a SATA interface and will be mounted: {{{ [ 727.076031] usb 1-2: new high speed USB device using ehci_hcd and address 4 [ 727.736450] usb 1-2: configuration #1 chosen from 1 choice [ 727.757057] scsi4 : SCSI emulation for USB Mass Storage devices [ 732.761591] scsi 4:0:0:0: Direct-Access HP v100w 4096 PQ: 0 ANSI: 0 CCS [ 732.763848] sd 4:0:0:0: Attached scsi generic sg2 type 0 [ 732.765576] sd 4:0:0:0: [sdb] 7831552 512-byte logical blocks: (4.00 GB/3.73 GiB) [ 732.772884] sd 4:0:0:0: [sdb] Write Protect is off [ 732.776462] sdb: sdb1 [ 732.782332] sd 4:0:0:0: [sdb] Attached SCSI removable disk }}} = Buffer I/O Errors = If you see errors related to Buffer I/O when attaching a USB Storage device, there are two ways to work around it. First, try using varying max_sectors settings, as such: {{{ sudo sh -c "echo 120 > /sys/block/sda/queue/max_sectors_kb" }}} Try values of 120, 64 and 32. If this does not resolve the issue, then you may need an unusual_dev entry for your device. It would look something like this: {{{ UNUSUAL_DEV(0x03eb , 0x2002, 0x0100, 0x9999, "Generic", "MusicDrive", US_SC_DEVICE, US_PR_DEVICE, NULL, US_FL_IGNORE_RESIDUE), }}} The vendor and device ID's can be obtained from the output of "lsusb". The entry would be placed in drivers/usb/storage/unusual_devs.h. If you cannot compile your own kernel, please file a bug report, and we'll attempt to compile a test module for you. = Bug Reports = If you are filing a bug report, please include the following as attachments along with a detailed description of your problem. * Initiate the problem situation, then quickly get the output of {{{dmesg}}} * Output of {{{uname -a}}} * Output of {{{lsb_release -a}}} * Output of {{{lsusb -v}}} * any other data relevant to your problem = Further Help = For help with mounting external drives, see [[Mount/USB]]. For further help in troubleshooting, ask on the [[Ubuntu:UbuntuForums|Ubuntu Forums]] at http://ubuntuforums.org/ ---- CategoryUsb