10-STABLE suspend failure

[Kevin Oberman]

Sometime in the past 6 months I lost the ability to suspend my ThinkPad
T520. I don't often suspend this system, so I just noticed it today when I
had it away from AC power for a while. It used to work just fine.
10.1-STABLE FreeBSD 10.1-STABLE #0 r280293: Fri Mar 20 11:28:08 PDT
2015     root at rogue:/usr/obj/usr/src/sys/GENERIC  amd64

When I attempt a suspend, I get errors from both graphics and disks.
drmn0: GEM idle failed, resume might fail
acpi0: device_suspend failed
ahcich1: Timeout on slot 29 port 0
ahcich1: is 00000000 cs 60000000 ss 60000000 rs 60000000 tfd d0 serr
00000000 cmd 000cdd17
(ada1:ahcich1:0:0:0): READ_FPDMA_QUEUED. ACB: 60 08 70 51 dd 40 06 00 00 00
00 00
(ada1:ahcich1:0:0:0): CAM status: Command timeout
(ada1:ahcich1:0:0:0): Retrying command
ahcich0: Timeout on slot 31 port 0
ahcich0: is 00000000 cs 80000000 ss 00000000 rs 80000000 tfd d0 serr
00000000 cmd 0000ff17
(ada0:ahcich0:0:0:0): FLUSHCACHE48. ACB: ea 00 00 00 00 40 00 00 00 00 00 00
(ada0:ahcich0:0:0:0): CAM status: Command timeout
(ada0:ahcich0:0:0:0): Error 5, Retries exhausted
(ada0:ahcich0:0:0:0): Synchronize cache failed

Anyone have any ideas on what broke?
--
Kevin Oberman, Network Engineer, Retired
E-mail: rkoberman at gmail.com