Date: Thu, 11 Sep 2008 09:23:10 -0700 From: Julian Elischer <julian@elischer.org> To: Rink Springer <rink@FreeBSD.org> Cc: Volker <volker@vwsoft.com>, Antony Mawer <fbsd-current@mawer.org>, current@freebsd.org, freebsd-usb@freebsd.org, Hans Petter Selasky <hselasky@c2i.net> Subject: Re: "legacy" usb stack fixes Message-ID: <48C945EE.4070805@elischer.org> In-Reply-To: <20080911103343.GH1413@rink.nu> References: <20080819211814.6CD685B4D@mail.bitblocks.com> <48B0EA50.2090105@mawer.org> <48B3299F.5080101@vwsoft.com> <200809111013.23994.hselasky@c2i.net> <20080911103343.GH1413@rink.nu>
next in thread | previous in thread | raw e-mail | index | archive | help
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, >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?48C945EE.4070805>