RE: netdevice problem - 1394 SPB-2 Drives

[Mark Knecht <mknecht@controlnet.com>]

Hi,
   First, I'm not the guy to make any decisions about how this might get
done in the 1394 driver stack. I'm a hardware guy and system oriented.
However, that said, the 1394 usage model is more similar to USB, in general,
than it is to SCSI. There are lots of 1394 devices. They serve lots of
purposes. And hot plugging is a basic part of the way 1394 works, at both
the hardware and software levels.

   Additionally, there are 1394 bridges coming which will link together many
1394 buses, and there are going to be both local and distant discovery
issues involved when devices are added and removed. I presume that
_eventually_ we'll want to be able to extend the hot plugging concepts to
find 1394 disk drives that are located a couple of miles away across some
1394b interface. But that's in the future.

   So, I think part of the issue here is that the 1394 stack is going to
have a fairly low level part that is handling the hardware part of notifying
the system that something has happened. Above that the 1394 stack will
probably need to let the hot plugging system know about certain device
changes, but possibly not about all devices. Do you see this software being
responsible when I plug in 1394 printers, cameras, speakers, home theatre
equipment, as well as disk drives? I'm not clear...

   Thanks for the opportunity to wave the flag for 1394!

Mark

-----Original Message-----
From: Oliver Neukum [mailto:Oliver.Neukum@lrz.uni-muenchen.de]
Sent: Thursday, January 18, 2001 3:18 PM
To: David Brownell; Mark Knecht;
linux-hotplug-devel@lists.sourceforge.net
Subject: Re: netdevice problem - 1394 SPB-2 Drives


On Thursday 18 January 2001 22:47, David Brownell wrote:
> >    How do you guys seeing 1394 disk drives fitting into the hot-plug
mix?
>
> Right on top of basic 1394 hotplug support!
>
> The hotplug bus support for PCI and USB is pretty similar ... how well
> do these map to the ieee1394 subsystem?

That's not the issue in this case. SCSI is the problem.
I've looked at that driver. It needs to deal with device addition/removal.

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.

At present hotplugging in this driver sucks and will continue to
do so until the scsi subsystem is extended.

Even then for configuration there's a need to further support.
The raw news about a device is of little use. You need the information about

partitions and other things.

	Regards
		Oliver

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