From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Goodwin Date: Sat, 20 Jan 2001 23:47:50 +0000 Subject: Re: 1394 SBP-2 Drives Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org Hi, > > > As there are a lot of device on a firewire bus, it > probably can't use the > > > pseudo host controller hack. And shouldn't - it's a hack, which is > > > unfortunately necessary for usb. > > > > I don't know where that came from, but notice I never said > > anything about such stuff. In fact, neither does the firewire > > code I glanced at -- Initiator/Target is the terminology. > > That's from usb-storage. It's the only currently working way > to get a device that uses the scsi command set to support > hotplugging. The USB storage and IEEE-1394 SBP-2 drivers (as well as ide-scsi for that matter) serve as both scsi low-level drivers and high-level protocol drivers for their respective busses... this is done in order to leverage the scsi command set and higher-level block drivers and filesystems. The primary difference between the two drivers (scsi-wise) is that the USB storage driver registers a new virtual SCSI host for each attached USB storage device, while the IEEE-1394 SBP-2 driver registers one SCSI host per IEEE-1394 bus, but maps each attached SBP-2 device as a virtual SCSI ID. > I was referring to the SPB-2 subclass of ieee1394 devices which like > usb-storage use the scsi command set. The driver for them indeed > is not part of the standard kernel. These disks (and scanners) are > the hardest case. If they work everything works in terms of > hotplugging. The main issues currently for the SBP-2 driver (and SCSI) are how to trigger and deal with scsi device addition or removal, and how to get drives mounted and unmounted as appropriate. The work being done on /sbin/hotplug can certainly be leveraged, and the scsi folk are talking about hooks to allow for event driven addition/removal of devices (in the scsi mid-level code). One additional issue to think about is "surprise" removal of storage devices (e.g. recovery and error handling after mounted drives with open files are hot-unplugged). ;-) Cheers, --James _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net http://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel