Very slow disk access using USB-SATA adapter on Pi 3 B+

[John F Carr]

I have a Raspberry Pi 3 B+ connected to a pair of drives via a USB to SATA adapter.  They worked fine on another arm64 system running then-CURRENT early this year, but now the drive is extremely slow on this week's CURRENT.  I'm getting about 1 transfer per second through the filesystem.  dd from the disk device moved about 64 kilobytes per second.

Sound familiar?  Any clues in the dmesg fragment below?

The slow drive is da1.  I'm not using da0.  That USB_ERR_STALLED doesn't look good.  The adapter gives the drives fake serial numbers which are identical.  No problem 8 months ago but maybe it is now.

FreeBSD 13.0-CURRENT #0 r355121: Wed Nov 27 07:50:23 UTC 2019
    root at releng1.nyi.freebsd.org:/usr/obj/usr/src/arm64.aarch64/sys/GENERIC arm64
FreeBSD clang version 9.0.0 (tags/RELEASE_900/final 372316) (based on LLVM 9.0.0)
WARNING: WITNESS option enabled, expect reduced performance.
[...]
usbus0 on bcm283x_dwcotg0
[...]
usbus0: 480Mbps High Speed USB v2.0
[...]
ugen0.8: <VIA Labs, Inc. USB2.0 Hub> at usbus0
uhub4 on uhub1
uhub4: <VIA Labs, Inc. USB2.0 Hub, class 9/0, rev 2.10/90.40, addr 8> on usbus0
uhub4: 4 ports with 4 removable, self powered
ugen0.9: <asmedia ASMT1053E> at usbus0
umass0 on uhub4
umass0: <asmedia ASMT1053E, class 0/0, rev 2.10/1.00, addr 9> on usbus0
umass0:  SCSI over Bulk-Only; quirks = 0x0100
umass0:0:0: Attached to scbus0
da0 at umass-sim0 bus 0 scbus0 target 0 lun 0
da0: <ASMT 2105 0> Fixed Direct Access SPC-4 SCSI device
da0: Serial Number 123456789012
da0: 40.000MB/s transfers
da0: 3815447MB (7814037168 512 byte sectors)
da0: quirks=0x2<NO_6_BYTE>
ue0: link state changed to UP
ugen0.10: <asmedia ASMT1053E> at usbus0
umass1 on uhub4
umass1: <asmedia ASMT1053E, class 0/0, rev 2.10/1.00, addr 10> on usbus0
umass1:  SCSI over Bulk-Only; quirks = 0x0100
umass1:1:1: Attached to scbus1
uhub_reattach_port: device problem (USB_ERR_STALLED), disabling port 3
da1 at umass-sim1 bus 1 scbus1 target 0 lun 0
da1: <ASMT 2105 0> Fixed Direct Access SPC-4 SCSI device
da1: Serial Number 123456789012
da1: 40.000MB/s transfers
da1: 3815447MB (7814037168 512 byte sectors)
da1: quirks=0x2<NO_6_BYTE>