umass panic (after detaching/attaching card-reader 3 times)

[Matthew Dillon]

:
:I would love to, if I could find hardware that reproduces the problem.  I
:went shopping for USB thumb drives a while back and only came up with
:working ones.
:
:I have a Soyo KT400 Dragon Lite machine at home.
:
:-- 
:Doug White                    |  FreeBSD: The Power to Serve
:dwhite at gumbysoft.com          |  www.FreeBSD.org

    It took me a while to reproduce the panic from the first bug report
    that was posted to our list, but I was finally able to do it by 
    plugging in three or four USB mass storage devices all at once,
    in various combinations before and after booting.  The key in reproducing
    the bug is to get the system to detach a UMASS during the boot sequence,
    that's what causes the (now disconnected) CAM bus rescan timeout to blow
    up.  For some unknown reason the UMASS/USB subsystem will often attach/
    deattach/reattach devices during boot, even though you haven't unplugged
    them.  I don't know why... it still happens in DFly but it no longer
    crashes.

    I have brought the DFly ISO image up to date and added a README.USB
    section and also an ehci.ko module (the rest of USB is already compiled
    into GENERIC), which should be enough for anyone having this problem
    to play around with the USB subsystem from a DragonFly ISO CD boot 
    without having to touch their hard drive.  The ISO is available here
    (around 70MB gzip'd, 200MB unzipped).  It's a fully live boot CD, just
    login as root.  You can even edit things in /etc, /tmp, /dev, etc...
    they are MFS mounts, of course.

	ftp://ftp.dragonflybsd.org/iso-images/dfly-20040317b.iso.gz

    I am curious if the people reporting the problem on FBsd-4 still have
    the problem when the above DFly ISO.  If not then I would say that 
    pretty much guarentees that my recent bug fixes (described in my previous
    posting to this list) have dealt with the issue.  If so then I have more
    work to do and would appreciate a bug report / dmesg output / backtrace
    from DDB if possible :-)

    p.s. the ISO fits on those cute mini CD-R's.

						-Matt