USB problems on FreeBSD-current and Raspberry Pi3B+, MMCCAM perhaps?

[bob prohaska]

On Sat, Jan 09, 2021 at 12:33:41PM -0800, bob prohaska wrote:
> A UGreen USB3 storage card adapter (model 30333) has stopped working
> with FreeBSD-current, reporting a stream of 
> 
> (da1:umass-sim1:1:0:0): TEST UNIT READY. CDB: 00 00 00 00 00 00 
> (da1:umass-sim1:1:0:0): CAM status: SCSI Status Error
> (da1:umass-sim1:1:0:0): SCSI status: Check Condition
> (da1:umass-sim1:1:0:0): SCSI sense: NOT READY asc:3a,0 (Medium not present)
> (da1:umass-sim1:1:0:0): Error 6, Unretryable error
> (da2:umass-sim1:1:0:1): TEST UNIT READY. CDB: 00 00 00 00 00 00 
> (da2:umass-sim1:1:0:1): CAM status: SCSI Status Error
> (da2:umass-sim1:1:0:1): SCSI status: Check Condition
> (da2:umass-sim1:1:0:1): SCSI sense: NOT READY asc:3a,0 (Medium not present)
> (da2:umass-sim1:1:0:1): Error 6, Unretryable error
> in what looks like an infinite loop (there are 4 daX devices on the adapter).
> 
> The present kernel displaying these errors is 
> FreeBSD 13.0-CURRENT (GENERIC-MMCCAM) #5 main-c255664-g4d64c7243d26: 
> Sat Jan  9 11:27:58 PST 2021
> 
> Unplugging the adapter restores normal operation.
> 
Well, maybe not always. The latest unplugging (with / on da0) caused
(noperiph:umass-sim0:0:-1:ffffffff): (pass4:umass-sim0:0:0:3): xpt_async(AC_PATH_DEREGISTERED)
Periph destroyed
(da3:umass-sim0:0:0:3): Periph destroyed
umass0: detached

panic: mountroot: unable to (re-)mount root.
cpuid = 2
time = 665
KDB: stack backtrace:
db_trace_self() at db_trace_self_wrapper+0x30
	 pc = 0xffff0000007593a0  lr = 0xffff00000011ad90
	 sp = 0xffff00004033e390  fp = 0xffff00004033e590

db_trace_self_wrapper() at vpanic+0x194
	 pc = 0xffff00000011ad90  lr = 0xffff000000454cc4
	 sp = 0xffff00004033e5a0  fp = 0xffff00004033e600

vpanic() at panic+0x44
	 pc = 0xffff000000454cc4  lr = 0xffff000000454a6c
	 sp = 0xffff00004033e610  fp = 0xffff00004033e6c0

panic() at vfs_mountroot+0x1854
	 pc = 0xffff000000454a6c  lr = 0xffff00000052c8fc
	 sp = 0xffff00004033e6d0  fp = 0xffff00004033e830

vfs_mountroot() at start_init+0x24
	 pc = 0xffff00000052c8fc  lr = 0xffff0000003e2848
	 sp = 0xffff00004033e840  fp = 0xffff00004033e8f0

start_init() at fork_exit+0x7c
	 pc = 0xffff0000003e2848  lr = 0xffff00000040eb78
	 sp = 0xffff00004033e900  fp = 0xffff00004033e950

fork_exit() at fork_trampoline+0x10
	 pc = 0xffff00000040eb78  lr = 0xffff00000077b5c8
	 sp = 0xffff00004033e960  fp = 0x0000000000000000

KDB: enter: panic
[ thread pid 1 tid 100002 ]
Stopped at      0
db>  

So it looks like there's some interference between da0 (boot device)
and da1 through da4, the device names used by the adapter. 

> Rebooting to 
> FreeBSD www.zefox.org 13.0-CURRENT FreeBSD 13.0-CURRENT #3 r361820: Sun Jun  7 22:19:00 PDT 2020     bob at www.zefox.org:/usr/obj/usr/src/arm64.aarch64/sys/GENERIC  arm64
> exhibits normal behavior, the adapter can be read and written without trouble.
> 
> As an aside, a Raspberry Pi4 8GB suffers even worse mischief when the adapter
> is connected, losing communication with the USB root device even after the
> adapter is unplugged.  A power cycle is required to recover. That system is
> Linux raspberrypi 5.4.83-v7l+ #1379 SMP Mon Dec 14 13:11:54 GMT 2020 armv7l GNU/Linux
> Since it implements onboard WiFi presumably it has some equivalent to MMCCAM.
> 
> Might this behavior have anything to do with MMCCAM ? 
> 
 Thanks for reading,
 
 bob prohaska