I have this device

 Bus 001 Device 008: ID 152d:2329 JMicron Technology Corp. / JMicron USA Technology Corp.

 http://www.eagletechusa.com/External_Enclosure/ET-CS2XMESU2-BK.htm

which is blacklisted in libatasmart:

 http://git.0pointer.de/?p=libatasmart.git;a=blob;f=atasmart.c;h=3ff033418a4d8e27f2828a9c0b474d1db9e545be;hb=54f846c2115e7addf5468a9c10ecf9ba844b946e#l2506

If I comment out the blacklist entry, the device indeed chokes (as in, it disconnects) when libatasmart is trying to read SMART status. However, it works fine with smartmontools

# smartctl -a /dev/sdb
smartctl 5.39 2009-11-30 r2990 [x86_64-redhat-linux-gnu] (local build)
Copyright (C) 2002-9 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF INFORMATION SECTION ===
Model Family:     Western Digital Scorpio Blue Serial ATA family
Device Model:     WDC WD5000BEVT-22ZAT0
Serial Number:    WD-WXE0A89K3530
Firmware Version: 01.01A01
User Capacity:    500,107,862,016 bytes
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   8
ATA Standard is:  Exact ATA specification draft version not indicated
Local Time is:    Mon Dec 14 10:03:51 2009 EST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x00)	Offline data collection activity
					was never started.
					Auto Offline Data Collection: Disabled.
Self-test execution status:      (   0)	The previous self-test routine completed
					without error or no self-test has ever 
					been run.
Total time to complete Offline 
data collection: 		 (13200) seconds.
Offline data collection
capabilities: 			 (0x7b) SMART execute Offline immediate.
					Auto Offline data collection on/off support.
					Suspend Offline collection upon new
					command.
					Offline surface scan supported.
					Self-test supported.
					Conveyance Self-test supported.
					Selective Self-test supported.
SMART capabilities:            (0x0003)	Saves SMART data before entering
					power-saving mode.
					Supports SMART auto save timer.
Error logging capability:        (0x01)	Error logging supported.
					General Purpose Logging supported.
Short self-test routine 
recommended polling time: 	 (   2) minutes.
Extended self-test routine
recommended polling time: 	 ( 154) minutes.
Conveyance self-test routine
recommended polling time: 	 (   5) minutes.
SCT capabilities: 	       (0x303f)	SCT Status supported.
					SCT Feature Control supported.
					SCT Data Table supported.

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x002f   100   253   051    Pre-fail  Always       -       0
  3 Spin_Up_Time            0x0027   182   180   021    Pre-fail  Always       -       1875
  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       17
  5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x002e   100   253   000    Old_age   Always       -       0
  9 Power_On_Hours          0x0032   100   100   000    Old_age   Always       -       4
 10 Spin_Retry_Count        0x0033   100   253   051    Pre-fail  Always       -       0
 11 Calibration_Retry_Count 0x0032   100   253   000    Old_age   Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       15
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   Always       -       7
193 Load_Cycle_Count        0x0032   200   200   000    Old_age   Always       -       42
194 Temperature_Celsius     0x0022   121   109   000    Old_age   Always       -       26
196 Reallocated_Event_Count 0x0032   200   200   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0030   100   253   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x0032   200   200   000    Old_age   Always       -       0
200 Multi_Zone_Error_Rate   0x0009   100   253   051    Pre-fail  Offline      -       0

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
No self-tests have been logged.  [To run self-tests, use: smartctl -t]


SMART Selective self-test log data structure revision number 1
 SPAN  MIN_LBA  MAX_LBA  CURRENT_TEST_STATUS
    1        0        0  Not_testing
    2        0        0  Not_testing
    3        0        0  Not_testing
    4        0        0  Not_testing
    5        0        0  Not_testing
Selective self-test flags (0x0):
  After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.