CAM status: Command timeout

[andrei at fazik.net.ua]

Hello,
After updating to 11.1 my home server can't boot with errors like
(ada0:ata2:0:0:0): WRITE_DMA48. ACB: 35 00 50 29 10 40 6c 00 0c 00
(ada0:ata2:0:0:0): CAM status: Command timeout
(ada0:ata2:0:0:0): Retrying command
for all 6 sata hdd(stripe from 2 raidz)
ACB different from boot to boot
Sometimes it even can boot, but in few minutes will hang with same errors.

Hardware: Supermicro X8DTN+-F / 6xWD1502FYPS-02W3B0 /2xE5649
HDDs connected to sata ports on baseboard.
If I add
hint.ata.2.mode=PIO4
hint.ata.3.mode=PIO4
hint.ata.4.mode=PIO4
hint.ata.5.mode=PIO4
to device.hints I'm able to boot but performance of IO becomes really disappointing.
Also, if I add something like "find / -name something" to zfs rc script, than boots fine.

If I roll back system to 11.0 all works fine again.
Any advise on debuging of this issue?
Also raised bug report some time ago for this issue
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221704