1 Reply Latest reply on Jun 10, 2012 4:12 PM by snahl

    How to get a fan temperature clamp to work for a hotswap backplane (AXX6DRV3GR) on a S5520SC workstation board?

    dcvanduyn

      Hi,

       

      Perhaps someone has the answer to my problem. I own an S5520SC workstation board, with an AXX6DRV3GR 6 drive hot swap backplane, mounted in a SC5500BASE chassis. Everyting is running on the latest frimware.

       

      The system works like a charm, however, the hotswap backplane (with 6 HDDs) runs a little too hot. So I had the idea to regulate the fan speed of "fan domain 2" in accordance to the temperature of the hot swap backplane. Fan domain 2 contains the fan directly mounted behind the hot swap backplane, in the SC5600BASE chassis.

       

      In order to do so, I modified the "HC_BMC.sdr" file, and added a temperature clamp record to the corresponding fan domain. Actually, this looks like it is pretty straight forward. Judging from the temperature sensor record for the hot swap backplane in the "HC_BMC.sdr" file:

       

         // Sensor Record Header
         005B   // Record ID
         51    // SDR Version
         01    // Record Type
         38    // Record Length

         // Record Key Bytes
         C0    // Sensor Owner ID
         00    // Sensor Owner LUN
         01    // Sensor Number

         // Record Body Bytes
         0F    // Entity ID
         01    // Entity Instance
         7F    // Sensor Initialization (7D)
         68    // Sensor Capabilities
         01    // Sensor Type
         01    // Event / Reading Base Type
         8532  // Assertion Event Mask    --[u,l][c,nc]=8532
         8532  // Deassertion Event Mask  --[u,l][c,nc]=8532
         1B1B  // Reading Mask & Settable / Readable Threshold Masks --[u,l][c,nc]=1B1B
         80    // Sensor Units 1
         01    // Sensor Units 2 --(Degree C)
         00    // Sensor Units 3
         00    // Linearization
         01    // M
         02    // M, Tolerance
         00    // B
         2C    // B, Accuracy
         10    // Accuracy, Accuracy Exp
         00    // R exp, B exp
         07    // Analog characteristic flags
         //------------------------------------------------------------------//
         1C    // Nominal Reading  (1Ch = 28.00C)
         2D    // Normal Maximum   (2Dh = 45.00C)
         0A    // Normal Minimum   (0Ah = 10.00C)
         //------------------------------------------------------------------//
         7F    // Sensor Maximum Reading
         80    // Sensor Minimum Reading
         //------------------------------------------------------------------//
         00    // Upper non-recoverable
         36    // Upper critical      (36h = 54.00C)
         32    // Upper non-critical  (32h = 50.00C)
         //------------------------------------------------------------------//
         00    // Lower non-recoverable
         00    // Lower critical       (00h = 0.00C)
         05    // Lower non-critical   (05h = 5.00C)
         //------------------------------------------------------------------//
         02    // Positive hysterisis
         02    // Negative hysterisis
         00    // Reserved
         00    // Reserved
         00    // OEM
         CD    // Type/Length Code
         'Pri 6HDD Temp'      // String Bytes

       

      This sensor is on IPMI (bus) address:

       

      C0    // Sensor Owner ID
      01    // Temperature Sensor Number -- (Pri 6HDD Temp)

       

      So the SDR clamp record, clamping at 30 degrees Celsius would be:

       

         // Sensor Record Header
         0203              // Record ID
         51                 // SDR Version
         C0                 // Record Type
         15                 // Record Length

         // Record Body Bytes
         570100           // Manufacturer ID
         0C                 // Record Subtype Value (Fan Speed Control SDR Record, rev 2)

         // Temperature Fan Control Record
         01                 // Record Version
         02                 // Fan Control Domain Number #2

         23                 // Normal Control Value (23h = PWM 35%)
         FF                 // Boost Control Value (FFh = PWM 255%)
         01                 // Ramp Step (1=1%)
         02                 // Scan Rate (2 Cycles)
         FF                 // Fan Profile Support

         // Clamp Type Temperature Sensor sub-record
         C0                 // Sensor Owner ID
         01                 // Temperature Sensor Number -- (Pri 6HDD Temp)
         50                 // Temp Sensor Fail Control Value (50h = PWM 80%)
         00                 // Sleep Control Value (Fan = off in sleep mode)
         42                 // [7:6]-Supported in S1 (1=yes); [5:3]-Reserved; [2:0]-Control Type (010b=Clamp)
         10                 // Temperature Info [7:6]-Reserved; [5:3]-Negative Hysteresis = 2; [2:0]-Positive Hysteresis = 0
         40                 // Ramp Contribution (0.064 %/s/C)
         00                 // Scan Rate
         1D                 // ClampTemp (1Dh = 29 degree C = 6HDD Max Temp)
         00                 // Clamp Flag

       

      Hence, as soon as the hot swap backplane temperature would cross the 29 degrees Celsius threshold, fan speed should start to increase to additionally cool the backplane.

       

      So far so good . . . .

       

      However, no matter what I do, the temperature clamp won't work with the temperature sensor of the hot swap backplane. Which is rather strange, because as far as I can judge from the specifications it should work like a charm.

       

      The clamp itself works, because if I replace the backplane sensor, in the above SDR record, with any of the other temperature sensors in the system (e.g. baseboard, front panel, CPU, IOH, MEM) one can actually see the temperature clamp regulating the fan speed. It wouldn't make sense, but in principle it proves the clamp works.

       

      The hotswap backplane temperature sensor itself is oke, as it perfectly outputs its temperature in the Intel Active System Console (Release 4.3). It hoovers around 35 degrees Celsius. This is way above the threshold of 29 degrees C, so the clamp should have come in to effect.

       

      Anybody have any suggestions to get this working. Much appreciated.

       

      Regards,

       

      Dave