Re: 8.0 USB "device problem, disabling port"

[Brian Buhrow <buhrow%nfbcal.org@localhost>]

	hello.  I've looked at this error message in the 5.2 stack and, if you
look in there, there's a lot of hand waving when the code encounters
conditions it doesn't understand.  That is to say, the error path doesn't
do a lot to diagnose the trouble, i.e. figure out if it's a power problem,
a speed matching issue or something else.  That said, I seem to encounter
it most when the port in question is behind a cascade of hub devices,
suggesting that stacks of nested hub devices are problematic for our stack.
I have a Dell workstation here, for example, where USB flash disks plugged
into the front panel ports of the machine generate these errors, but if the
flash sticks are plugged into ports on the back, all is well.
	My suggestion is to look in the -current source to see if the uhub
code has gotten smarter about handling error conditions.   The USB stack
has received a lot of attention since 5.2 and 8.x were released.  Perhaps
you can take some ideas from there and back port them to your tree and thus
get better diagnostics and, possibly working fixes for the problem itself.
If that's not fruitful, I suggest looking at the FreeBSD USB stack source
code for similar inspiration.


	I'm sure I've said nothing you don't already know, but hopefully it
helps spark an idea anyway.

-Brian

On Mar 11, 10:41am, Mouse wrote:
} Subject: 8.0 USB "device problem, disabling port"
} In 8.0, and at least one earlier version, when the kernel doesn't like
} a USB device for some reason the message generated just says "device
} problem, disabling port" (with the hub name and port number).
} 
} Would I be out of place to suggest that this is a little...light on
} useful information?  It's admittedly not on a par with the infamous
} Nifty Doorways Eleventy upgrade message, but it's definitely further in
} that direction than I'd like.  (As I used to tell the first-level
} people back when I was doing second-level support, "it doesn't work" is
} not a usable problem report.)
} 
} In the tree I'm using at work, I've just thrown printfs into
} usbd_new_device.  But that's a bit ugly, probably not the best approach
} (though I can certainly send a diff for what I have if anyone wants).
} Thoughts?
} 
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