dave_user
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→Operational Mode
Then there are four energy-intensive operations.
==== Power state ====
The power state of kernel can be obtain with follow command:
<pre>
root@desk-mx93-rev0:~# cat /sys/power/state
freeze mem
</pre>
In this case are present:
* <code>mem</code> (Suspend)
* <code>freeze</code>
To use <code>mem</code> & <code>freeze</code> there are need setup a wake up source, on example the console UART as a wake up source
<pre>
echo enabled > /sys/class/tty/ttyLP0/power/wakeup
</pre>
Change the power status like the follow command:
<pre>
echo mem > /sys/power/state
</pre>
<pre>
root@desk-mx93-rev0:~# echo mem > /sys/power/state
[ 485.684754] PM: suspend entry (deep)
[ 485.764566] Filesystems sync: 0.076 seconds
[ 485.769692] Freezing user space processes
[ 485.775189] Freezing user space processes completed (elapsed 0.001 seconds)
[ 485.782180] OOM killer disabled.
[ 485.785418] Freezing remaining freezable tasks
[ 485.791072] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
[ 485.798472] printk: Suspending console(s) (use no_console_suspend to debug)
</pre>
write something on console:
<pre>
...
[ 485.842439] imx-dwmac 428a0000.ethernet eth1: Link is Down
[ 485.842745] imx-dwmac 428a0000.ethernet eth1: FPE workqueue stop
[ 485.857765] fec 42890000.ethernet eth0: Link is Down
[ 485.858356] PM: suspend devices took 0.052 seconds
[ 485.860465] Disabling non-boot CPUs ...
[ 485.860876] psci: CPU1 killed (polled 0 ms)
[ 485.862050] Enabling non-boot CPUs ...
[ 485.862201] Detected VIPT I-cache on CPU1
[ 485.862246] cacheinfo: Unable to detect cache hierarchy for CPU 1
[ 485.862255] GICv3: CPU1: found redistributor 100 region 0:0x0000000048060000
[ 485.862291] CPU1: Booted secondary processor 0x0000000100 [0x412fd050]
[ 485.862564] CPU1 is up
[ 485.926184] imx-dwmac 428a0000.ethernet eth1: configuring for phy/rgmii-id link mode
[ 485.936472] imx-dwmac 428a0000.ethernet eth1: No Safety Features support found
[ 485.936488] imx-dwmac 428a0000.ethernet eth1: IEEE 1588-2008 Advanced Timestamp supported
[ 485.936676] imx-dwmac 428a0000.ethernet eth1: FPE workqueue start
[ 486.027552] PM: resume devices took 0.164 seconds
[ 486.028522] remoteproc remoteproc0: releasing imx-rproc
[ 486.125601] OOM killer enabled.
[ 486.128751] Restarting tasks ... done.
[ 486.135997] random: crng reseeded on system resumption
[ 486.141289] PM: suspend exit
root@desk-mx93-rev0:~# [ 488.996995] fec 42890000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[ 488.998759] imx-dwmac 428a0000.ethernet eth1: Link is Up - 1Gbps/Full - flow control rx/tx
[ 489.004784] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 489.021014] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
</pre>
==== Measurements ====