Date: Fri, 3 May 2002 10:33:54 -0400 From: Michael Lucas <mwlucas@FreeBSD.ORG> To: Josef Karthauser <joe@tao.org.uk> Cc: current@FreeBSD.ORG Subject: Re: Status of USB subsystem. Message-ID: <20020503103354.A4370@blackhelicopters.org> In-Reply-To: <20020503132248.GA9101@genius.tao.org.uk>; from joe@tao.org.uk on Fri, May 03, 2002 at 02:22:48PM %2B0100 References: <20020503132248.GA9101@genius.tao.org.uk>
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Joe, Thank you for taking the time to document your work-in-progress. I, for one, vastly appreciate what you're doing with the USB subsystem. I think a lot of our "community" issues could be greatly improved by more people doing exactly what you've done here. OK, back to the peanut gallery. ==ml On Fri, May 03, 2002 at 02:22:48PM +0100, Josef Karthauser wrote: > Dear all, > > I wanted to write to talk about the status of our USB stack in > -current because there has been some concern expressed over the > last week about where were are at with it, and more importantly > when the bugs are going to be ironed out. In particular there has > been a call to backout it all out back to a time when it worked. > > The background is that I've been porting the developments that > NetBSD has had into FreeBSD. In some cases we were two years behind > the state of the art. Today we're in a much better shape; most of > the controller code and device API is pretty much the same as > NetBSD's now, and that means that it should be relatively easy to > port the ehci USB2 controller code. A lot of the devices are now > synced too, although in general these have diverged over the period > a lot more than the controller code has. > > With a prevailing wind behind us we should now have been in a much > better position than we were when I started this work at the beginning > of the year. I think that we almost are, but there are a few bugs > that at the moment are eluding me, they could be because the bug > exists in NetBSD, or because of some FreeBSDism that I've not > realised, or just because of some code that's not been ported yet. > I don't know, but I am working on it. > > Here are the issues that I know about: > > * There's a disconnect bug, which I've tied down to interupt pipes not > cancelling properly when a device is unplugged. What this leads > to is an xfer that repeats, and locks the usb subsystem. I've > experienced it with uhub and ums, but it's possible, and probably, > that other devices are effected to. I made some headway on this > last night, and am in communication with the NetBSD author who's > helping me track the problem down. > > * There's an attach problem with the aue network device, and possibly > cue and kue too. This bug appears to have been around for a while > but has just been revealed by the recent memory manager changes. > It caused an attach time panic due to a bad memory allocation. > NetBSD's aue driver is different from ours and possibly doesn't > have the same problem. > > * Problems with ulpt. These appear to be in NetBSD also. I've got > a usb printer (HP office jet) and so potentially have the resources > to track the problem down, but as it's not entirely broken for all > users, this problem is less important than the two about IMO. > > If anyone has any others that they've not revealed I'd like to know > please. > > Also, if anyone particularly fancies helping out I'd be very grateful. > This is my first bout into the kernel, and although I've got all > the tools (remote debugger etc) I'm still a little slow with using > them. Mail me privately if you've got the time and energy to help > out. > > I'm prepared to back everything out if required, but my feeling is > that we're a stone's throw away from solving these problems; it's > just I'm throwing stones slower than a seasoned kernel hacker would. > It would be a shame to take such a large step backwards if it's > just a small step forwards that's required. > > The last known good date was just before the uma commit, i.e. > -D20020319\ 0900. Of course there have been some kernel infrastructure > changes since then so it's not just a matter of backing out the > sys/dev/usb directory to that date. There are some changes that > need to be retained, but they should be obvious for anyone who wants to > do this locally. > > I ask for your patience in getting to the bottom of these problems, and > wanted people to know that I am taking these issues serious, something > that might not be clear because I've not communicated much about it on > the lists. > > The good news is that once these issues have been resolved we are > in a good position to port the drivers that NetBSD have but we've > not seen yet. There are lots, like uaudio and uvisor, that we should > take avantage of. I hope that these will follow in the not too > distant future. > > Regards, > Joe > > p.s. I'm away for the weekend and so if you don't get a reply to any > email until the early part of next week it's not because I'm ignoring > you. -- Michael Lucas mwlucas@FreeBSD.org, mwlucas@BlackHelicopters.org http://www.oreillynet.com/pub/q/Big_Scary_Daemons Absolute BSD: http://www.nostarch.com/abs_bsd.htm To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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