On Mon 2018-11-12 21:11:32, Jacek Anaszewski wrote: > On 11/12/2018 08:05 PM, Pavel Machek wrote: > > Hi! > > > >>>>> My system looks like this: > >>>>> > >>>>> input16::capslock tpacpi::bay_active tpacpi::standby > >>>>> input16::numlock tpacpi::dock_active tpacpi::thinklight > >>>>> input16::scrolllock tpacpi::dock_batt tpacpi::thinkvantage > >>>>> input5::capslock tpacpi::dock_status1 tpacpi::unknown_led > >>>>> input5::numlock tpacpi::dock_status2 tpacpi::unknown_led2 > >>>>> input5::scrolllock tpacpi:green:batt tpacpi::unknown_led3 > > > >>> But it is not just for backwards compatibility. See my examples above, > >>> it is needed to tell which device the LED is asociated with, and it is > >>> absolutely required for USB devices (for example). > >> > >> For USB devices there is already ledtrig-usbport available, which > >> provides sysfs interface for defining and reading the usb ports, > >> the status of which the LED indicates. Since the USB devices can be > >> attached/removed dynamically, it would be impossible to reflect > >> the associations in the LED class device name. > > > > I'm not talking USB activity. I'm talking USB devices with LEDs on > > them, like for example keyboards. > > > > Please take a look at example above. input16::numlock ; > > input5::numlock . You absolutely need device part. > > It would be redundant since there is "device" symbolic link > created in given LED class device sysfs directory, pointing to the > corresponding input device directory, like in case of my USB > keyboard: You are right I forgot about the device symlink, and it partly helps with the USB keyboard case... But you still need the device part. Sysfs will not like two directories named "::numlock". > #/sys/class/leds/input5::scrolllock$ ls -l > total 0 > -rw-r--r-- 1 root root 4096 Nov 12 20:22 brightness > lrwxrwxrwx 1 root root 0 Nov 12 20:22 device -> ../../input5 > -r--r--r-- 1 root root 4096 Nov 12 20:22 max_brightness > drwxr-xr-x 2 root root 0 Nov 12 20:22 power > lrwxrwxrwx 1 root root 0 Nov 12 20:04 subsystem -> > ../../../../../../../../../../../class/leds > -rw-r--r-- 1 root root 4096 Nov 12 20:22 trigger > > Because userspace needs that information? > > > > Say you have raid array, with "error" leds for each drive (your list > > already contains "hdderr"). Now userland detects problem with hdparm > > on /dev/sdi. It would like to turn on corresponding LED. > > > > How do you propose we do that? > > Similarly as in case of USB keyboard. Not really, I'm afraid. Hard drives have no red LEDs on them (and the LED would not be visible, anyway) so the "device" symlink in such case would point to some kind of i2c LED controller. Eventually we'll need to have two devices for each LED. "Controller this is on" -- in device symlink and "device this talks about". Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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