CAM breaks USB [was Re: USB causing boot to hang]

[Steve Kargl]

On Fri, Dec 06, 2019 at 12:23:16PM -0800, Steve Kargl wrote:
> I updates /usr/src to r355452, and updated by kernel and
> world.  Upon rebooting, verbose boot messages susgests
> the system is hanging when USB starts to attach.  With
> the 3-week kernel verbose boot shows:
> 
> ...
> pcm4: <Realtek ALC889 (Rear Digital)> at nid 30 on hdaa1
> pcm4: Playback:
> pcm4:      Stream cap: 0x00000005 AC3 PCM
> pcm4:         PCM cap: 0x000e05f0 16 20 24 bits, 32 44 48 88 96 192 KHz
> pcm4:             DAC: 6
> pcm4: 
> pcm4:     nid=30 [pin: SPDIF-out (Grey Jack)]
> pcm4:       + <- nid=6 [audio output] [src: pcm]
> pcm4: 
> pcm4: Mixer "vol" -> "none": child=0x00000010
> pcm4: Mixer "pcm": parent="vol"
> pcm4: Soft PCM mixer ENABLED
> pcm4: Playback channel set is: Front Left, Front Right, 
> pcm4: Playback channel matrix is: 2.0 (unknown)
> usbus0: 5.0Gbps Super Speed USB v3.0
> usbus1: 12Mbps Full Speed USB v1.0
> ...
> 
> end with a prompt on the console.  With today's kernel,
> boot is hung after the last pcm4: message and no usbus0
> is displayed.
> 
> The booting kernel/system is a 
> 
> % uname -a
> FreeBSD 13.0-CURRENT #1 r354658: Wed Nov 13 11:23:32 PST 2019,  amd64
> 
> Again, the failing kernel is r 355452
> 

The problem seems to be caused 355010.  This is a commit to
fix CAM, which seems to break USB.

-- 
Steve