J4076-01 User's Manual
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Chapter 3 Sub-System configuration Setup
3.6.5.6 How to manually change PWM (fan speed) for all Cooling
elements
Cooling control element
BYTE/BIT
7
6
5
4
3
2
1
0
0
COMMON CONTROL
SELECT
PRDFAIL DISABLE RST SWAP
Reserved
1
RQST
IDENT
Reserved
2
Reserved
3
Reserved RQST FAIL RQST ON
Reserved
REQUESTED SPEED CODE
The "RQST IDENT" for Cooling is defined in the bit7, byte1 and the
"REQUESTED SPEED CODE" is defined in the bit2 ~ 0, byte3 of the "Cooling
control element" in the SES specification. Set "RQST IDENT" bit to disable
the smart fan function, and then change PWM or fan speed for all
Cooling elements by setting the "REQUESTED SPEED CODE" bits. Clear
"RQST IDENT" bit to enable the smart fan function again. Please disable
the smart fan function before changing PWM or fan speed. Only Cooling
element 0 supports this feature. We use the software package "sg3_utils"
on Linux for example, and have a SAS HBA and a cable to connect your
host with the expander.
(A) Show the device for AIC Expander Controller (canister)
$ sg_map -i
/dev/sg2 AIC 12G 4U76swap: Hub 0c07
(B) Set "RQST IDENT" of Cooling element 0 to disable the smart fan
function
$ sg_ses --descriptor=SystemCoolingElement01 --set=1:7:1 /dev/sg2
(C) Set "REQUESTED SPEED CODE" of Cooling element 0 to change PWM
or fan speed for all Cooling elements. Set "REQUESTED SPEED CODE"=7
(100% PWM) for example.
$ sg_ses --descriptor=SystemCoolingElement01 --set 3:2:3=7 /dev/sg2
