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<p></p> <p><b>New page</b></p><div>== Overview ==<br /> The Linux kernel for CM-T3530 may be built with support for very low power sleep mode and dynamic frequency scaling. <br /> {{Important|Use {{filename|cm_t35_pm_defconfig}} kernel configuration file to build the Linux kernel with enabled power management features.}}<br /> <br /> == Frequency scaling ==<br /> The Linux kernel for CM-T3530 utilizes [http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=tree;f=Documentation/cpu-freq;hb=HEAD cpu-freq] framework for dynamic frequency scaling.<br /> <br /> The CPU frequency can be changed on the fly using the following commands:<br /> echo userspace &gt; /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor<br /> echo &lt;frequency&gt; &gt; /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed<br /> <br /> The {{parameter|frequency}} should be specified in MHz.<br /> <br /> == Suspend to RAM ==<br /> The Linux kernel for CM-T3530 supports very low power sleep mode. Use the following commands to suspend the system:<br /> <br /> mount -t debugfs debug /sys/kernel/debug/<br /> echo &lt;wakeup timeout&gt; /sys/kernel/debug/pm_debug/wakeup_timer_seconds <br /> echo 1 &gt; /sys/kernel/debug/pm_debug/enable_off_mode <br /> echo 1 &gt; /sys/kernel/debug/pm_debug/voltage_off_while_idle <br /> echo disabled &gt; /sys/devices/platform/serial8250/power/wakeup <br /> echo disabled &gt; /sys/devices/platform/serial8250.0/power/wakeup <br /> echo disabled &gt; /sys/devices/platform/serial8250.1/power/wakeup <br /> echo disabled &gt; /sys/devices/platform/serial8250.2/power/wakeup <br /> echo mem &gt; /sys/power/state<br /> <br /> == Limitations ==<br /> * The only wake-up source is the internal OMAP3 timer<br /> * The USB host driver should be compiled as loadable kernel module. It must be unloaded to allow the system enter the sleep mode.<br /> * The USB OTG driver should be excluded from the kernel<br /> * The video capture drivers should be excluded from the kernel<br /> <br /> == See also ==<br /> * [http://elinux.org/OMAP_Power_Management OMAP Power Management]<br /> <br /> <br /> [[Category:Linux|Power Management]]<br /> [[Category:CM-T3530|Linux: Power Management]]</div>

Mike