USB detach/attach hangs with 7.0-RELEASE and 7.1-PRERELEASE

Ronald Klop ronald-freebsd8 at
Mon Oct 6 20:29:26 UTC 2008

In that case I'm out of options. Maybe somebody else on the list can  



On Fri, 03 Oct 2008 16:51:35 +0200, Henrik Friedrichsen <henrik at>  

> USB support in the BIOS? What kind of support does the BIOS provide that  
> you can disable?
> I'm only able to disable the USB device, but that'd turn it off  
> completely :(
> Henrik.
> On Mon, Sep 29, 2008 at 10:05:02PM +0200, Ronald Klop wrote:
>> On Mon, 29 Sep 2008 02:46:15 +0200, Bruce M Simpson  
>> <bms at>
>> wrote:
>> >Hi,
>> >
>> >I've noticed some general instability with plugging in or removing USB
>> >devices with FreeBSD 7.x, even when the devices are not actively in  
>> use.
>> >
>> >I had this happen with umass and ucom devices 3 times today. The  
>> machine
>> >hangs solid, there are no obvious signs of a panic or trap to DDB. I
>> >can't provide backtraces unfortunately -- these hangs happen on both my
>> >laptop and desktop, and I usually have X running -- if I had more
>> >specific information, I'd open a PR.
>> >
>> >Again, there seems to be no reason why this should happen, the devices
>> >are off-the-shelf consumer items known to work with existing drivers,
>> >and have been repeatedly used in other OSes without these hangs
>> >happening; consider this an "anecdotal report".
>> >
>> >[For some reason my IBM laptop will often not allow me to break into  
>> DDB
>> >on a driver related panic, and will just immediately reboot -- I lack
>> >free time to track down exactly why this could be.
>> >My desktop has a USB keyboard and this appears not to be supported by
>> >DDB, I ordered a PS/2 keyboard which hasn't arrived, but that's another
>> >story.]
>> >
>> >thanks
>> >BMS
>> On my computer I had to disable USB support in the BIOS because it
>> 'conflicted' with USB support of FreeBSD.
>> FreeBSD still detects USB and all connected devices.
>> Maybe this helps on your computer also.
>> Ronald.
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