Date: Sat, 29 Dec 2007 15:40:49 -0500 From: Ben Kelly <bkelly@vadev.org> To: Hans Petter Selasky <hselasky@c2i.net> Cc: freebsd-usb@freebsd.org Subject: Re: FreeBSD P4 USB project - precompiled kernels available for download Message-ID: <A5B4BA42-E8DF-4385-9272-9567A6EC787C@vadev.org> In-Reply-To: <200712290938.31371.hselasky@c2i.net> References: <200712290214.15919.hselasky@c2i.net> <08127556-0DC2-41E2-9C22-EB9C07333629@vadev.org> <200712290938.31371.hselasky@c2i.net>
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On Dec 29, 2007, at 3:38 AM, Hans Petter Selasky wrote: > On Saturday 29 December 2007, Ben Kelly wrote: >> It didn't look like there had been any USB changes in there >> recently. Has the USB development moved completely to p4? > > Just for the time being. I will update my SVN repo soon so that you > can get > the source code and compile for yourself. Thanks! >> I would like to try the new stack, but I am guessing I will need to >> patch it for usb/95173 in order to use my umass device. > > Usually it is best if patches go into FreeBSD current first, > because else I > will have to keep track of the patches I take in. Regarding your > patch, it > looks OK, except it would be nice if the patch could be modified so > that it > automatically detects these quirks. Because adding quirks is a bad > solution > in the long run. I agree that quirks are not the best solution. Unfortunately, though, I don't think it will be possible to detect the problem and dynamically disable sync'ing. At least this particular USB-to-disk controller seems to lockup when the sync command is issued. It requires a power cycle to recover the device. It did occur to me, however, that perhaps it would make sense to disable sync'ing for all umass devices by default and then add a quirk to enable the feature on devices where its known to be beneficial. This is based on the (perhaps dubious) theory that most umass devices probably do not do a lot of caching because of the risk of being disconnected at any time. I didn't pursue this option, though, since I thought it would be more controversial and harder to get applied to the tree. > Maybe you have another USB mass storage device you can test ? I think I can probably find one. Eventually I would like to test my hard drive enclosure, though, since I use it the most often currently. I probably won't be able to run the tests until after the new year. Thanks again. - Benhome | help
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