Most recent kernel where this bug did not occur: 2.6.14.3 behaves     
differently from earlier versions (I tried 2.6.7, 2.6.11 and 2.6.13), but both 
have bugs when using ehci_hcd. I didn't try with older kernels than 2.6.7. 
  
Distribution: Mandrake Linux, but those kernels were self-compiled from    
kernel.org sources    
Hardware Environment: IBM Thinkpad R50 laptop, Pentium M.    
Software Environment: hmm... gcc-3.4.3, x.org, kde-3.5, was that the question?    
Problem Description:     
  This is about a 160G USB-2.0 external hard drive, in a 3.5" case.   
 
  With 2.6.7, 2.6.11 or 2.6.13 the drive is recognized using ehci_hcd, I mount 
it, but when using the drive I get a USB disconnect very soon (as mentionned in 
Bug 4057, but the comments in that bug ask for separate reports to be filed for 
specific problems).  
  
 Nov 25 10:37:31 Asterix kernel: Linux version 2.6.13.2 (root@Asterix) (gcc 
version 3.4.3 (Mandrakelinux 10.2 3.4.3-7mdk)) #2 Sat Sep 24 21:08:35 CEST 2005 
[...] 
Nov 25 10:37:31 Asterix kernel: ehci_hcd 0000:00:1d.7: Intel Corporation 
82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller 
Nov 25 10:37:31 Asterix kernel: ehci_hcd 0000:00:1d.7: debug port 1 
Nov 25 10:37:31 Asterix kernel: ehci_hcd 0000:00:1d.7: new USB bus registered, 
assigned bus number 4 
Nov 25 10:37:31 Asterix kernel: ehci_hcd 0000:00:1d.7: irq 11, io mem 
0xc0000000 
Nov 25 10:37:31 Asterix kernel: PCI: cache line size of 32 is not supported by 
device 0000:00:1d.7 
Nov 25 10:37:31 Asterix kernel: ehci_hcd 0000:00:1d.7: USB 2.0 initialized, 
EHCI 1.00, driver 10 Dec 2004 
[...] 
 
Nov 25 17:01:33 Asterix kernel: usb 4-4: new high speed USB device using 
ehci_hcd and address 2 
Nov 25 17:01:34 Asterix kernel: SCSI subsystem initialized 
Nov 25 17:01:34 Asterix kernel: Initializing USB Mass Storage driver... 
Nov 25 17:01:34 Asterix kernel: scsi0 : SCSI emulation for USB Mass Storage 
devices 
Nov 25 17:01:34 Asterix kernel: usbcore: registered new driver usb-storage 
Nov 25 17:01:34 Asterix kernel: USB Mass Storage support registered. 
Nov 25 17:01:34 Asterix kernel: usb-storage: device found at 2 
Nov 25 17:01:34 Asterix kernel: usb-storage: waiting for device to settle 
before scanning 
Nov 25 17:01:40 Asterix kernel:   Vendor: SAMSUNG   Model: SP1604N           
Rev:  0 0 
Nov 25 17:01:40 Asterix kernel:   Type:   Direct-Access                      
ANSI SCSI revision: 00 
Nov 25 17:01:40 Asterix kernel: usb-storage: device scan complete 
Nov 25 17:01:40 Asterix scsi.agent[4278]: disk 
at /devices/pci0000:00/0000:00:1d.7/usb4/4-4/4-4:1.0/host0/target0:0:0/0:0:0:0 
Nov 25 17:01:40 Asterix kernel: SCSI device sda: 312581808 512-byte hdwr 
sectors (160042 MB) 
Nov 25 17:01:40 Asterix kernel: sda: assuming drive cache: write through 
Nov 25 17:01:40 Asterix kernel: SCSI device sda: 312581808 512-byte hdwr 
sectors (160042 MB) 
Nov 25 17:01:40 Asterix kernel: sda: assuming drive cache: write through 
Nov 25 17:01:40 Asterix kernel:  sda: sda1 
Nov 25 17:01:40 Asterix kernel: Attached scsi disk sda at scsi0, channel 0, id 
0, lun 0 
[but later on: ] 
Nov 25 17:32:25 Asterix kernel: usb 4-4: USB disconnect, address 2 
Nov 25 17:32:25 Asterix kernel: scsi0 (0:0): rejecting I/O to device being 
removed 
Nov 25 17:32:25 Asterix kernel: Buffer I/O error on device sda1, logical block 
592 
Nov 25 17:32:25 Asterix kernel: lost page write due to I/O error on sda1 
Nov 25 17:32:25 Asterix kernel: Aborting journal on device sda1. 
Nov 25 17:32:25 Asterix kernel: journal commit I/O error 
(and then this is repeated for other logical blocks)  
   
With 2.6.14.3 (and verbose debug enabled for usb in kernel config), things are 
different: 
Nov 30 11:36:53 Asterix kernel: hub 4-0:1.0: state 5 ports 6 chg 0000 evt 0010 
Nov 30 11:36:53 Asterix kernel: ehci_hcd 0000:00:1d.7: GetStatus port 4 status 
001803 POWER sig=j CSC CONNECT 
Nov 30 11:36:53 Asterix kernel: hub 4-0:1.0: port 4, status 0501, change 0001, 
480 Mb/s 
Nov 30 11:36:53 Asterix kernel: hub 4-0:1.0: debounce: port 4: total 100ms 
stable 100ms status 0x501 
Nov 30 11:36:53 Asterix kernel: ehci_hcd 0000:00:1d.7: GetStatus port 4 status 
001002 POWER sig=se0 CSC 
Nov 30 11:36:53 Asterix kernel: hub 4-0:1.0: state 5 ports 6 chg 0000 evt 0010 
Nov 30 11:36:53 Asterix kernel: ehci_hcd 0000:00:1d.7: GetStatus port 4 status 
001803 POWER sig=j CSC CONNECT 
Nov 30 11:36:53 Asterix kernel: hub 4-0:1.0: port 4, status 0501, change 0001, 
480 Mb/s 
Nov 30 11:36:53 Asterix kernel: hub 4-0:1.0: debounce: port 4: total 100ms 
stable 100ms status 0x501 
Nov 30 11:36:53 Asterix kernel: ehci_hcd 0000:00:1d.7: GetStatus port 4 status 
001002 POWER sig=se0 CSC 
Nov 30 11:36:53 Asterix kernel: hub 4-0:1.0: state 5 ports 6 chg 0000 evt 0010 
Nov 30 11:36:53 Asterix kernel: ehci_hcd 0000:00:1d.7: GetStatus port 4 status 
001803 POWER sig=j CSC CONNECT 
 
in syslog (going on for ever), and in messages: 
 
Nov 30 11:37:03 Asterix kernel: usb 4-4: new high speed USB device using 
ehci_hcd and address 42 
Nov 30 11:37:04 Asterix kernel: usb 4-4: new high speed USB device using 
ehci_hcd and address 45 
Nov 30 11:37:06 Asterix kernel: usb 4-4: new high speed USB device using 
ehci_hcd and address 50 
Nov 30 11:37:06 Asterix kernel: usb 4-4: new high speed USB device using 
ehci_hcd and address 52 
Nov 30 11:37:09 Asterix kernel: usb 4-4: new high speed USB device using 
ehci_hcd and address 60 
Nov 30 11:37:10 Asterix kernel: usb 4-4: new high speed USB device using 
ehci_hcd and address 64 
 
Since I read about ehci_hcd being the problem, I did rmmod ehci_hcd, and then 
it all works fine: 
 
Nov 30 11:39:01 Asterix kernel: ehci_hcd 0000:00:1d.7: USB bus 4 deregistered 
Nov 30 11:39:01 Asterix kernel: ACPI: PCI interrupt for device 0000:00:1d.7 
disabled 
Nov 30 11:39:01 Asterix kernel: usb 2-2: new full speed USB device using 
uhci_hcd and address 2 
Nov 30 11:39:01 Asterix kernel: usb 2-2: Product: USB2.0 Storage Device 
[etc. it proceeded to the normal initialization] 
 
Feel free to ask for more info if needed.