USB 2.0 with bogus Data Rate

[Bernd Walter]

On Mon, Mar 21, 2005 at 11:42:40PM +0000, Carlos Silva aka|Danger_Man| wrote:
> Julian Elischer wrote:
> 
> >
> >
> >Carlos Silva aka|Danger_Man| wrote:
> >
> >>Hi hackers,
> >>
> >>I have a little problem with my external disk drive, my data transfer 
> >>rate is 1.000MB/s.
> >>I have USB 2.0 so the rate is larger, right?
> >>Somebody has an idea how to enlarge the rate?
> >
> >
> >
> >the data rate is bogus because it is printed by the scsi/cam code
> >which doesn't know about USB speeds.
> >
> >This has been improved in 6.x and may flow back to 5.4..
> >in the meantime, ignore that number and use
> >dd if=/dev/da0 of=/dev/null bs=64k
> >to see what your rate really is..
> 
> 
> Here is the rate:
> 
> osiris# dd if=/dev/da0 of=/dev/null bs=64k
> ^C16+0 records in
> 16+0 records out
> 1048576 bytes transferred in 14.741515 secs (71131 bytes/sec)
> osiris#

Are you shure that the device is really a high speed one?
USB 2.0 doesn't explizitly mean this.
In the list below it looks like the device is handled by an VIA
uhci controller - that is definitivley full speed only.
usbdevs -v will show you details about the current detection.
Moreover VIA controllers are known to cause problems.
But it's even much too slow for full speed.
There must be something elese - e.g. an IRQ problem.
The best choise would be to replace the controller with an NEC based
one.

> >>osiris# dmesg | grep usb && dmesg | grep da0
> >>usb0: <Intel 82371AB/EB (PIIX4) USB controller> on uhci0
> >>usb0: USB revision 1.0
> >>usb1: <VIA 83C572 USB controller> on uhci1
> >>usb1: USB revision 1.0
> >>usb2: <VIA 83C572 USB controller> on uhci2
> >>usb2: USB revision 1.0
> >>ehci_pci_attach: companion usb1
> >>ehci_pci_attach: companion usb2
> >>usb3: EHCI version 0.95
> >>usb3: companion controllers, 2 ports each: usb1 usb2
> >>usb3: <EHCI (generic) USB 2.0 controller> on ehci0
> >>usb3: USB revision 2.0
> >>GEOM: create disk da0 dp=0xc2d96850
> >>da0 at umass-sim0 bus 0 target 0 lun 0
> >>da0: <USB 2.0 Storage Device 0100> Fixed Direct Access SCSI-0 device
> >>da0: 1.000MB/s transfers
> >>da0: 190782MB (390721968 512 byte sectors: 255H 63S/T 24321C)
> >>osiris#
> >>
> >>osiris# usbdevs
> >>addr 1: UHCI root hub, Intel
> >>addr 1: UHCI root hub, VIA
> >>addr 1: UHCI root hub, VIA
> >>addr 2: USB 2.0 Storage Device, Acer Labs
> >>addr 1: EHCI root hub, (0x1106)
> >>osiris#
> >>
> >>osiris# camcontrol devlist
> >><USB 2.0 Storage Device 0100>      at scbus0 target 0 lun 0 (da0,pass0)
> >>osiris#

-- 
B.Walter                   BWCT                http://www.bwct.de
bernd at bwct.de                                  info at bwct.de