I'm sure you are right in your diagnosis (absent any knowledge to the contrary). Now what's the treatment? Would uas black-list provide a work-araound? If so a detailed recipe will be needed by me ... Fix to the code? Ideal, but takes lots longer, so a work-around may be needed for a while David -----Original Message----- From: Oliver Neukum [mailto:oneukum@xxxxxxxx] Sent: 09 November 2020 09:30 To: David C. Partridge; linux-usb@xxxxxxxxxxxxxxx Subject: Re: Issues with LaCie USB3 drive and UAS Am Sonntag, den 08.11.2020, 10:56 +0000 schrieb David C. Partridge: > LUbuntu 20.04.1 > > root@charon:/home/amonra# lsusb > Bus 002 Device 006: ID 059f:105f LaCie, Ltd 2Big Quadra USB3 > > Trying to format the above drive using mkfs.ext4 /dev/sdc2 > > Initially got a 120s Kernel timeout which I resolved by setting the timeout > to 0 > > However I got LOTS of message groups in the system log looking like this: > > Nov 04 06:18:51 charon kernel: scsi host5: uas_eh_device_reset_handler start > Nov 04 06:18:51 charon kernel: sd 5:0:0:0: [sdc] tag#0 uas_zap_pending 0 > uas-tag 1 inflight: > Nov 04 06:18:51 charon kernel: sd 5:0:0:0: [sdc] tag#0 CDB: Write Same(10) > 41 00 e8 ea 47 fc 00 00 04 00 Write Same? What you are seeing is that the error handling is running non-stop. I suspect that the device does not understand WRITE SAME. Regards Oliver