Date: Wed, 25 May 2011 18:01:24 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: "Shah, Vishal" <Vishal.Shah@netapp.com> Cc: "Ranaweera, Samantha" <Samantha.Ranaweera@netapp.com>, "Faylor, Christopher" <Christopher.Faylor@netapp.com>, Hans Petter Selasky <hselasky@FreeBSD.org>, freebsd-usb@FreeBSD.org Subject: Re: System hang in USB umass module while processing panic Message-ID: <4DDD19C4.6090705@FreeBSD.org> In-Reply-To: <86FB7D63AF95574BB762C0C3E1F269150D8B14AB@RTPMVEXC1-PRD.hq.netapp.com> References: <86FB7D63AF95574BB762C0C3E1F269150D8B14AB@RTPMVEXC1-PRD.hq.netapp.com>
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on 19/05/2011 22:27 Shah, Vishal said the following: > In FreeBSD 8 USB driver, commands are asynchronously sent from umass layer onto > the wire, in other words, multiple threads are involved before the command is > sent from the umass layer all the way to the wire. Since the usb_proc is not > scheduled current process keeps waiting for the command to complete, hence the > hang. Is this a known issue? If yes, is there a fix available? Are there any > plans of adding a synchronous path to send the command to the device? Any > information regarding this issue is much appreciated. >From your description this sounds like a problem in USB driver. I am not an expert in USB code, looks like some polling prodding would have to be added there (if it's not there yet). Hans Petter may be a better contact for this issue. I am not sure if I can help you more. -- Andriy Gapon
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