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[309] La terre vue d'ailleurs / Informatique / Zaurus / wake up on RTC alarm for the Netwalker
Zaurus :
By default, the Netwalker does not support waking up on RTC alarm, which implies that it cannot be used as a PDA. It has a calendar program (Sunbird), and alarms can be set on events, but the Netwalker will raise the alarm only if the device is on at this time... not good for a PDA !

Actually, the hardware does support waking up on RTC alarm, but this functionality is already used... by the battery drivers ! Any alarm you set will be erased by the drivers of the battery when suspending the Netwalker. It seems that the battery need to be checked every 30 minutes when the device is suspended.

So here is a patch that modifies the battery drivers so as it honors the previously set RTC alarm if it is closer in time. The patch is intended to be applied on the Netwalker's Linux kernel from See this how to for compiling and flashing the Linux kernel on the Netwalker.

With this patch, the Netwalker can now wake up on RTC alarm. You can verify that by running the commands:
sudo echo 0 > /sys/class/rtc/rtc0/wakealarm
sudo echo `date '+%s' -d '+2minutes'` > /sys/class/rtc/rtc0/wakealarm
And then suspend your Netwalker. It should wake up 2 minutes later.

You can also find below my .config kernel configuration file. I've also disabled the Netwalker's quick keys since they are constantly starting apps even if I don't touch them ; if you want to keep them working, change CONFIG_TOUCHKEY_MXC in .config.

However, wake up on RTC alarm is only the first step for using the Netwalker as a PDA: the next step consists in creating RTC alarm from the calendar program. Stay tuned!


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