Rink Springer wrote: > On Thu, Sep 11, 2008 at 10:13:22AM +0200, Hans Petter Selasky wrote: >> I also see crashes with my new stuff and the umass driver when the USB device >> is un-plugged too early. The backtraces I've got so far does not indicate a >> USB problem, though .... > > That is correct, this is a bug in CAM. More specifically, CAM does not > handle the removal of busses well. There are two possible options: > > 1) Obviously, fix CAM to handle this scenarion > DragonflyBSD seems to have a lot of fixes in this area, which I > intend to take a look at 'some day' (no thanks to $reallife...) > > 2) Create a CAM bus per USB bus > I think this is reasonable, and it makes a lot more sense than the > one-bus-per-device approach that we have now. The idea is that > every USB controller hub creates a CAM bus, and umass(4) attaches to > this bus instead of creating its own. Of course, until CAM is fixed, > detaching PCMCIA or equivalent USB cards will still cause panics, but > it would be a lot better than it is now... > This is how it was originally. There was a reason that it was changed, so make sure you look into the history to figure out what the tradeoff was. > Personally, I'd like to see option 2 implemented in the USB2 stack, as > it avoids the issue and makes a lot more sense from user perspective > (I'm probably onot the only one who gets scared by 'camcontrol devlist' > if you have a single MP3 player which advertises 2 disks :-)) > > Regards, >Received on Thu Sep 11 2008 - 14:23:10 UTC
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