disk woes: revive w/o-reboot after SATA "START_STOP FAILED"?

[Jim Meyering]

Jim Meyering wrote:
> Hello,
>
> I've just returned one relatively new disk drive[*],
> and hope I'm not about to return another...
>
>     [*] It was a 1TB Samsung ecogreen, and some strenuous testing
>      would reliably provoke I/O errors which would apparently
>      damage the disk enough to force an increase in the SMART
>      Reallocated_Sector_Ct metric.  My final test added about 600
>      to that count.  Of all my other disks, some over 5 years old,
>      only 1 had a single Reallocated_Sector_Ct.  The rest were 0.
>
> Anyhow, this time it's my newest drive, a 1.5TB Samsung.
> Most of the time it is spun down, but spins up and works fine
> when I need it, which is once a day or so, for backups.
> But today, there was no trace of it at all.
> /dev/sdb had disappeared altogether.  Ominous.
> This is up-to-date F12 w/stock untainted 2.6.31.9-174.fc12.x86_64
> on an Intel Q9450.
>
> dmesg has clues:
>
>     ...
>     usb 1-5.2: new low speed USB device using ehci_hcd and address 40
>     usb 1-5.2: New USB device found, idVendor=046d, idProduct=c03e
>     usb 1-5.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
>     usb 1-5.2: Product: USB-PS/2 Optical Mouse
>     usb 1-5.2: Manufacturer: Logitech
>     usb 1-5.2: configuration #1 chosen from 1 choice
>     input: Logitech USB-PS/2 Optical Mouse as /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5.2/1-5.2:1.0/input/input29
>     generic-usb 0003:046D:C03E.001A: input,hidraw1: USB HID v1.10 Mouse [Logitech USB-PS/2 Optical Mouse] on usb-0000:00:1a.7-5.2/input0
>
> [maybe related?
>  The above are common events provoked by my turning off/on the
>  monitor+hub that my kbd and mouse are usually plugged into. ]
>
> Here's the bad part:
>
>     ata3.00: exception Emask 0x10 SAct 0x0 SErr 0x4000000 action 0xe frozen
>     ata3.00: irq_stat 0x00000040, connection status changed
>     ata3: SError: { DevExch }
>     ata3.00: cmd ec/00:01:00:00:00/00:00:00:00:00/00 tag 0 pio 512 in
>              res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x10 (ATA bus error)
>     ata3.00: status: { DRDY }
>     ata3: hard resetting link
>     ata3: SATA link down (SStatus 0 SControl 300)
>     ata3: hard resetting link
>     ata3: SATA link down (SStatus 0 SControl 300)
>     ata3: limiting SATA link speed to 1.5 Gbps
>     ata3: hard resetting link
>     ata3: SATA link down (SStatus 0 SControl 310)
>     ata3.00: disabled
>     ata3: EH complete
>     ata3.00: detaching (SCSI 2:0:0:0)
>     sd 2:0:0:0: [sdb] Synchronizing SCSI cache
>     sd 2:0:0:0: [sdb] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
>     sd 2:0:0:0: [sdb] Stopping disk
>     sd 2:0:0:0: [sdb] START_STOP FAILED
>     sd 2:0:0:0: [sdb] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK

FYI, halted, reseated SATA connectors, rebooted, and it's back,
seemingly as good as new.  SMART reports no problem.
Fingers crossed.