Comment 28 for bug 1318218

I have the same issue on my desktop computer that is configured to suspend when inactive. There have two SATA disks and 1 PATA disk on this box and only one disk seems to have issues while suspending. Desktop hangs while suspending and needs a hard reset. Kernel message before hang:

Apr 11 18:34:00 phoebe kernel: [46916.180338] ata3: exception Emask 0x40 SAct 0x0 SErr 0x800 action 0x7
Apr 11 18:34:00 phoebe kernel: [46916.180352] ata3: SError: { HostInt }
Apr 11 18:34:00 phoebe kernel: [46916.180363] ata3: hard resetting link
Apr 11 18:34:00 phoebe kernel: [46916.671824] ata3: softreset failed (device not ready)
Apr 11 18:34:00 phoebe kernel: [46916.671830] ata3: applying PMP SRST workaround and retrying
Apr 11 18:34:00 phoebe kernel: [46916.843775] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
Apr 11 18:34:00 phoebe kernel: [46916.854172] ata3.00: configured for UDMA/133
Apr 11 18:34:00 phoebe kernel: [46916.867797] ata3: EH complete
Apr 11 20:12:15 phoebe kernel: [ 0.000000] Initializing cgroup subsys cpuset

Disk having issues:
 *-disk
       description: ATA Disk
       product: WDC WD10EZEX-07Z
       vendor: Western Digital
       physical id: 0.0.0
       bus info: scsi@2:0.0.0
       logical name: /dev/sdb
       version: 80.0
       serial: WD-WCC1S0911072
       size: 931GiB (1TB)
       capabilities: gpt-1.00 partitioned partitioned:gpt
       configuration: ansiversion=5 guid=af7b25e8-6b9d-0363-6045-bd10f7b3f818 sectorsize=4096

Kernel version: Linux phoebe 3.13.0-49-generic #81-Ubuntu SMP Tue Mar 24 19:29:48 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Setting min_power in /sys/class/scsi_host/host3/link_power_management_policy
seems to work.