之前《都是檔案惹的禍？》裡，我們提過︰
在 Raspbian 的世界裡，一切都是『檔案』。這是真的嗎？從古早的 Unix 系統開始，就用著一種『統一』unified 的觀點來看待檔案。假如說 『程式』是執行檔很好了解，可是講到『硬體裝置』不過是特殊檔呢？……
就讓我們透過『 Sysfs 』── 是 Linux 2.6 所提供的一種『虛擬檔案系統』 VFS virtual files system 。這個檔案系統不僅可以把『裝置』 devices 和『驅動程式』 device drivers 的資訊從『核心』 kernel 內部輸出到『使用者空間』 user space ，也可以用來對裝置和驅動程式做『設定』。── 來控制『系統 ACT LED』，與 GPIO 『建立聯繫』吧！
# 為什麼一定得是 root 呢？可以只用 sudo 嗎？？ sudo -s echo none > /sys/class/leds/led0/trigger echo 1 >/sys/class/leds/led0/brightness echo 0 >/sys/class/leds/led0/brightness echo 1 >/sys/class/leds/led0/brightness echo 0 >/sys/class/leds/led0/brightness exit
Ah Ha！！這樣想要有顆『閃爍』的『小星星』，怕是不可得的了，何不閱讀《 Advanced Bash-Scripting Guide 》一下，寫個『 Shell 』程式呢？？
─── 《PHYSICAL COMPUTING ︰《二》 GPIO 初探》
承上篇，燒錄 SPI Flash 時發生的白色 LED 閃閃閃事件，使作者注意到 Armbian 開機後，只是白、紅兩個 LED 亮著，沒有任何用途耶？
rock64@rock64:~ls input1::capslock input1::kana input1::scrolllock standby-led input1::compose input1::numlock power-led usb-switch rock64@rock64:/sys/class/leds
cat /sys/class/leds/{standby-led,power-led}/trigger [none] rc-feedback kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock mmc0 mmc1 timer oneshot heartbeat default-on [none] rc-feedback kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock mmc0 mmc1 timer oneshot heartbeat default-on
由於查不到有關說明文件，故而直接考之以『電路圖』呦！
ROCK64_Schematic_v2.0_20171019.pdf
這時一目了然，綠色 LED 只是插了電沒的指示燈☺
sudo reboot ︰ 白亮、紅滅、綠亮
sudo poweroff ︰ 白滅、紅滅、綠亮
其後於 PINE64 論壇裡偶讀
t4_4t 04-19-2018, 03:07 AM
Controllable LEDs are red and white LEDs
The green LED is a power supply lamp, it lights up when power is supplied.
The green LED is a power supply lamp, it lights up when power is supplied.
Lighting can not be controlled.> flash when there is disk activity
I think that it refers to things such as “USB-HDD”, but it can not be done at present.
I think that it refers to things such as “USB-HDD”, but it can not be done at present.
You need to add code to realize the function to the kernel.—-
With the latest Ver dts (4.4.120)
linux, default-trigger = “disk-activity”
With the latest Ver dts (4.4.120)
linux, default-trigger = “disk-activity”
It already has the above setting.But, the 4.4.xx kernel does not support this keyword(“”disk-activity”).
It is supported keyword at Main-line-kernel (Ver 4.16.xx, ..)
But, this keyword is for activity of “ata-disk”.For this reason, in the current rock64, setting “disk-activity” is meaningless for any kernel.
But, this keyword is for activity of “ata-disk”.For this reason, in the current rock64, setting “disk-activity” is meaningless for any kernel.
只能莞爾一笑了◎