Re: USB4BSD release candidate number 3 - request for review

From: M. Warner Losh <imp_at_bsdimp.com>
Date: Wed, 05 Nov 2008 09:01:11 -0700 (MST)
In message: <20081105100433.GA43232_at_rink.nu>
            Rink Springer <rink_at_FreeBSD.org> writes:
: On Wed, Nov 05, 2008 at 02:18:17AM -0700, M. Warner Losh wrote:
: > In message: <200811050914.44225.hselasky_at_c2i.net>
: >             Hans Petter Selasky <hselasky_at_c2i.net> writes:
: > : On Wednesday 05 November 2008, Lars Engels wrote:
: > : > Mounting a umass device, removing it and doing an 'ls' on the mountpoint
: > : > freezes the system, I thought this should not happen with the new stack?
: > : 
: > : It is not a USB problem. It is the CAM layer that is hanging on the disk.
: > 
: > Sure it is CAM layer and not buffer cache or filesystem code?
: 
: Well, the CAM layer problem will immediately first - it does not like
: CAM busses disappearing. Once this is fixed or avoided and the problem
: still shows up, we can blame buffer cache / filesystem code.
: 
: As I suggested before, a good fix is to create one CAM bus per USB root
: hub, and use that to attach all umass devices to. This will also get rid
: of the one-bus-per-umass-device which is visually unappealling.

That might work.

It might also be useful to see if the DragonFly patches to allow this
port over or not...

Warner
Received on Wed Nov 05 2008 - 15:03:02 UTC

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