On my computer, I'm running Kubuntu dapper with kernel 2.6.15-27-686 on a dual-Pentium-3-Mainboard (output of lspci attached).

I don't know it that's connected with this issue, but I get sporadic problems with my USB-2.0-memory stick not being properly recognized by the kernel.

Right after booting the computer, it usually works, but (Murphy's Law...) always when I need to quickly transfer a file, there is no /dev/sda... entry created, and dmesg says something like:

[quote]
[17393482.236000] usb 5-1: new high speed USB device using ehci_hcd and address 4
[17393483.236000] ehci_hcd 0000:00:0f.2: Unlink after no-IRQ?  Controller is probably using the wrong IRQ.
[17393493.780000] usb 5-1: device not accepting address 4, error -110
[17393493.892000] usb 5-1: new high speed USB device using ehci_hcd and address 5
  [....]
[17393958.608000] usb 5-1: new high speed USB device using ehci_hcd and address 9
[17393970.152000] usb 5-1: device not accepting address 9, error -110
[17394247.388000] ehci_hcd 0000:00:0f.2: remove, state 1
[17394247.388000] usb usb5: USB disconnect, address 1
[/quote]

OK, right before inserting the USB-2.0-memory stick, I plugged in a USB-1.1-USB-connected-USB-storage-capable digital camera, and it was successfully recognized*. (I'm attaching the full output of dmesg too; the according messages are just before the dmesg lines quoted above in this posting)

After entering "sudo rmmod ehci_hcd" and "sudo modprobe ehci_hcd", the USB-2.0-stick works again; dmesg:

[quote]
[17394247.400000] ehci_hcd 0000:00:0f.2: USB bus 5 deregistered
[17394247.400000] ACPI: PCI interrupt for device 0000:00:0f.2 disabled
[17394253.320000] ACPI: PCI Interrupt 0000:00:0f.2[C] -> GSI 19 (level, low) -> IRQ 185
[17394253.320000] ehci_hcd 0000:00:0f.2: EHCI Host Controller
[17394253.324000] ehci_hcd 0000:00:0f.2: new USB bus registered, assigned bus number 5
[17394253.324000] ehci_hcd 0000:00:0f.2: irq 185, io mem 0xe3040000
[17394253.324000] ehci_hcd 0000:00:0f.2: USB 2.0 started, EHCI 1.00, driver 10 Dec 2004
[17394253.324000] hub 5-0:1.0: USB hub found
[17394253.324000] hub 5-0:1.0: 4 ports detected
[17394259.484000] usb 5-1: new high speed USB device using ehci_hcd and address 2
[17394259.636000] scsi2 : SCSI emulation for USB Mass Storage devices
[17394259.636000] usb-storage: device found at 2
[17394259.636000] usb-storage: waiting for device to settle before scanning
[17394264.640000]   Vendor: memory    Model: USB2.0            Rev: 1.00
[17394264.640000]   Type:   Direct-Access                      ANSI SCSI revision: 02
[17394264.640000] SCSI device sda: 1999360 512-byte hdwr sectors (1024 MB)
[17394264.640000] sda: Write Protect is off
[17394264.640000] sda: Mode Sense: 03 00 00 00
[17394264.640000] sda: assuming drive cache: write through
[17394264.644000] SCSI device sda: 1999360 512-byte hdwr sectors (1024 MB)
[17394264.644000] sda: Write Protect is off
[17394264.644000] sda: Mode Sense: 03 00 00 00
[17394264.644000] sda: assuming drive cache: write through
[17394264.644000]  sda: sda1
[17394264.644000] sd 2:0:0:0: Attached scsi removable disk sda
[17394264.644000] sd 2:0:0:0: Attached scsi generic sg0 type 0
[17394264.648000] usb-storage: device scan complete
[/quote]

I don't think that reverting to slow-speed USB is an option nowadays.



*: (Besides the issue that KDE doesn't show the "media:/"-URL, but simply a not working (because of the HAL-Subsystem and the missing /etc/fstab-entry) "/media", when I klick on "media" under "system:/" in Konqueror, but that doesn't belong here...)