help in USB ports numbering/identification

[Jeff Vian]

On Mon, 2006-04-03 at 11:16 +0200, Michal Szymanski wrote:
> Hi,
> 
> I am having hard time trying to connect a device designed as save-disk
> for digital cameras to a FC3/FC4 machines. The device is marked USB 2.0
> High Speed and carries also memory card reader (3 slots).
> 
> When I connect it to the PC, I get:
> 
> usb 3-2: new full speed USB device using uhci_hcd and address 8
> usb 3-2: not running at top speed; connect to a high speed hub
> scsi10 : SCSI emulation for USB Mass Storage devices
> usb-storage: device found at 8
> usb-storage: waiting for device to settle before scanning
>   Vendor: DCB       Model:      HS-HD        Rev: 2.23
>   Type:   Direct-Access                      ANSI SCSI revision: 00
> SCSI device sdc: 156301488 512-byte hdwr sectors (80026 MB)
> sdc: assuming drive cache: write through
> SCSI device sdc: 156301488 512-byte hdwr sectors (80026 MB)
> sdc: assuming drive cache: write through
>  sdc: sdc1
The drive was assigned a partition ID (sdc1) so it can be mounted that
way.

> Attached scsi disk sdc at scsi10, channel 0, id 0, lun 0
>   Vendor: DCB       Model:      HS-CF        Rev: 2.23
>   Type:   Direct-Access                      ANSI SCSI revision: 00
> Attached scsi removable disk sdd at scsi10, channel 0, id 0, lun 1
> ... (similar for other memory card slots, just different lun numbers)
> 
> So, it works as "full speed" only, with a rate of 1MB/s which is not
> acceptable for 80GB disk.
> 
> At first I though the first two lines mean that the USB port used is not
> capable of High Speed. But then I connected to the VERY SAME port
> another device - memory card reader (no disk) and got:
> 
> usb 1-4: new high speed USB device using ehci_hcd and address 12
                                          ^^^^^^^^^
I believe the USB 2.0 driver is ohci-hcd.  It seems that you may not be
getting the proper driver associated for high speed operation.

Mine loads the ohci-hcd driver and works at high speed.
This may be port, cable, or device, and if you have a hub between the
machine and the drive/card reader it can affect that as well.

> scsi9 : SCSI emulation for USB Mass Storage devices
> usb-storage: device found at 12
> usb-storage: waiting for device to settle before scanning
>   Vendor: SMSC      Model: USB 2 HS-CF       Rev: 2.16
>   Type:   Direct-Access                      ANSI SCSI revision: 00
> SCSI device sdc: 4001760 512-byte hdwr sectors (2049 MB)
> ... (other slots) ...
> 
> So there are two problems:
> 
> 1. Why does the device not work at 480 Mbps,
>From what I read the drive is seen and should be usable.  The card
reader slots on the other hand do not get a recognized partition and are
not mountable until/unless there is actually a card in the slot.
> 
> 2. What do all these USB numbers mean: 1-4, 3-2?
> I guessed one of those should should somehow point to the USB port used
> but it seems it does not. No single number repeats although the cable
> was plugged into the same port.

Each time a device is seen it is assigned a unique port for addressing
purposes.  It also gets a unique device name for the same reason.  My
usb drive can be on port 1,2,3,.....    and it also can be sda, sdb,
sdc, .....

These ports and names do timeout and get reused, but I do not know the
exact specs for  the length of time used.  I see the reuse if I wait for
some time before I reconnect something and it then may get the same id
it previously had.

> 
> any ideas, explanations?
> 
> regards, Michal.

With my card reader, when I connect it with no cards installed I get
this in dmesg.

sd 4:0:0:0: Attached scsi generic sg0 type 0
  Vendor: IC        Model: USB Storage-CFC   Rev: 322E
  Type:   Direct-Access                      ANSI SCSI revision: 00
sd 5:0:0:0: Attached scsi removable disk sdb
sd 5:0:0:0: Attached scsi generic sg1 type 0
  Vendor: IC        Model: USB Storage-SMC   Rev: 322E
  Type:   Direct-Access                      ANSI SCSI revision: 00
sd 5:0:0:1: Attached scsi removable disk sdc
sd 5:0:0:1: Attached scsi generic sg2 type 0
  Vendor: IC        Model: USB Storage-MMC   Rev: 322E
  Type:   Direct-Access                      ANSI SCSI revision: 00
sd 5:0:0:2: Attached scsi removable disk sdd

None of the above are usable partitions, However, when I insert a card I
get this:

SCSI device sdd: 1984001 512-byte hdwr sectors (1016 MB)
sdd: Write Protect is off
sdd: Mode Sense: 00 00 00 00
sdd: assuming drive cache: write through
SCSI device sdd: 1984001 512-byte hdwr sectors (1016 MB)
sdd: Write Protect is off
sdd: Mode Sense: 00 00 00 00
sdd: assuming drive cache: write through
 sdd: sdd1


After it is defined as sdd1 I can use it as a mounted filesystem.

HTH
Jeff