Temparature printout broken on tempminmax device once drive has been below 0C

[nadeau]

This is the output(below) I get from an SSD that has been in a temperature chamber.

Output ain't pretty anymore, used to be something like 23 (min/max 10/77)

I created a patch on github for that:
​https://github.com/fnadeau/smartmontools

I understand that you might not be interested in this patch for various reasons(drivedb.h not backward compatible, too many undocumented drive, etc.) Anyhow, I thought you might be interested.

smartctl 6.1 2013-03-16 r3800 [x86_64-linux-3.10.9-200.fc19.x86_64] (local build)
Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     SandForce Driven SSDs
Device Model:     KINGSTON SVP200S3480G
Serial Number:    50026B7226020429
LU WWN Device Id: 5 0026b7 226020429
Firmware Version: 501ABBF0
User Capacity:    480 103 981 056 bytes [480 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS, ACS-2 T13/2015-D revision 3
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Fri Aug 23 13:13:12 2013 EDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

.......

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000f   120   120   050    Pre-fail  Always       -       0/0
.......
194 Temperature_Celsius     0x0022   242   083   000    Old_age   Always       -       242 (0 239 0 83 0)
.......
242 Lifetime_Reads_GiB      0x0032   000   000   000    Old_age   Always       -       2

[Christian Franke]

Thanks for the patch.

IMO its complexity and the break of backward compatibility is not needed. I will enhance the current heuristics used by tempminmax format such that signed 8-bit values are handled properly. This would then also work for other drives using this format in the rare case of actual negative temperatures.

[Christian Franke]

Patch for -v,tempminmax format. Handles negative temperatures and WDC counter.

[Christian Franke]

Please apply above patch and test "smartctl -A ..." with affected devices.

[Christian Franke]

r3966.