[ltp] USB Drive Transfer Rate

[Frank Schaeckermann]

> ensure that ehci-hcd is loaded.
-----------------------------------------------------------
lsmod | grep "usb\|hci" (before attaching the drive):

usbserial              18460   0  [visor]
ehci-hcd               17772   0  (unused)
usb-uhci               23632   0  (unused)
usbcore                63916   1  [hci_usb visor usbserial ehci-hcd
                                    usb-uhci hid]
-----------------------------------------------------------
 > What about the dmesg output when you attach the drive?

dmesg (after attaching the drive):

Mar 11 11:40:49 R99WCY73 kernel: hub.c: new USB device 00:1d.7-4, 
assigned address 7
Mar 11 11:40:49 R99WCY73 kernel: usb.c: USB device 7 (vend/prod 
0x5e3/0x702) is
not claimed by any active driver.
Mar 11 11:40:52 R99WCY73 /etc/hotplug/usb.agent: Setup usb-storage for 
USB product 5e3/702/2
Mar 11 11:40:52 R99WCY73 kernel: Initializing USB Mass Storage driver...
Mar 11 11:40:52 R99WCY73 kernel: usb.c: registered new driver usb-storage
Mar 11 11:40:52 R99WCY73 kernel: scsi1 : SCSI emulation for USB Mass 
Storage devices
Mar 11 11:40:52 R99WCY73 kernel:   Vendor: IBM-DJSA  Model: -220 
       Rev: 0811
Mar 11 11:40:52 R99WCY73 kernel:   Type:   Direct-Access 
       ANSI SCSI revision: 02
Mar 11 11:40:52 R99WCY73 kernel: Attached scsi disk sda at scsi1, 
channel 0, id
0, lun 0
Mar 11 11:40:52 R99WCY73 kernel: SCSI device sda: 39070080 512-byte hdwr 
sectors (20004 MB)
Mar 11 11:40:52 R99WCY73 kernel:  sda: sda1
Mar 11 11:40:52 R99WCY73 kernel: USB Mass Storage support registered.
Mar 11 11:40:54 R99WCY73 devlabel: devlabel service started/restarted

-----------------------------------------------------------
lsmod | grep "usb\|hci" (after attaching the drive):

usb-storage            45184   0
usbserial              18460   0  [visor]
ehci-hcd               17772   0  (unused)
usb-uhci               23632   0  (unused)
scsi_mod               87396   3  [usb-storage sd_mod ide-scsi]
usbcore                63916   1  [usb-storage hci_usb visor usbserial
                                    ehci-hcd usb-uhci hid]
-----------------------------------------------------------

As we say in Germany "clever like a snake" I just did another test...

Before attaching the drive I removed the usb-uhci module leaving just 
the ehci-hcd running (killing my bluetooth connection to my mobile phone 
in the process and thus not able to send this message until that is 
restored ;-) ) and now hdparm reports 6 to 7 MB per second transfer 
rates! Go figure!

I'll keep an eye on the situation but for now it seems to be solved! 
Except somebody comes an tells me that 7MB/sec is far less than actual 
possible as well *grin*

Frank