Re: Samsung SP1614N + aborting sbp2 command

From: Stefan Richter <stefanr_at_s5r6.in-berlin.de>
Date: Thu 20 May 2004 - 15:01:16 CEST
Message-Id: <200405201258.i4KCwKaY026682@einhorn.in-berlin.de>

On 19 May, Simeon Penev wrote:
> i still have the
> problem that it cannot get attached when i load sbp2. In dmesg i get messages
> from the ohci1394 like "node changed", but when i make mount -> "the device
> doesn't exist". No message is brought up by sbp2, like it's normaly done when
> the harddisk is found and attached to /dev/sda. I need to restart the machine
> (sometimes more than ones) so i can access /dev/sda.

The following steps are taken before the disk is accessible:
- Linux' pci subsystem recognizes the 1394 adapter
- ohci1394 is loaded (manually or by a boot script) and brings
  the adapter up
- the disk's node is detected on the bus (by self-id packets that
  are sent by each node's physical layer hardware and received by
  the adapter chip)
- the ieee1394 base driver queries the type of the external
  device (by reading its config rom; in case of SBP2 bridges, the
  rom is built on- the-fly by the bridge's firmware after the
  disk drive spun up)
- according to the device type found in the rom, the base driver
  binds the sbp2 driver to the unit
- sbp2 sends a login request to the unit
- when login is granted by the bridge's link controller, sbp2
  adds the device to Linux' scsi subsystem
- the scsi driver scans the device and makes device files
  available (in case of harddisks, sg and sd files for the disk
  and for its partitions, if a partition table can be read)

Depending on which step fails, it may suffice to reload the sbp2
driver or the ohci1394 driver -- or power-cycle the disk --
instead of rebooting the PC.

-- 
Stefan Richter
-=====-=-=-- -=-= =-=--
http://arcgraph.de/sr/
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Received on Thu May 20 15:01:41 2004

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