On 21.06.21 21:43, Hans de Goede wrote: Hi, > The LED API actually has specific features which are typically > only used with kbd-backlights, such as the brightness_hw_changed > attribute which was specifically added to allow userspace to > monitor when a laptops embedded controller changes the kbd-backlight > brightness in response to a Fn + somekey hotkey keypress, so that > userspace can show an on-screen-display notification that the > kbd brightness has changed (like how it typically does for > audio volume changes too) and also showing the new brightness > level. See: Documentation/ABI/testing/sysfs-class-led for > the docs for the /sys/class/leds/<led>/brightness_hw_changed yes, that's great. but it seems we're still lacking a direct standard way for associating an input device with the corresponding backlight LED. Or am I missing something ? >> Looks like a very complicated way to do that. But actually I've never >> understood why I should use this strange upower thing anways :p > > Just because you don't have a use for it does not mean that it > is not useful (and widely used) in cases where people use Linux > as a desktop OS, rather then for more embedded cases. I'm actually using Linux on desktop for over 25 years now. But let's go back to the kernel side. >> In general, LED class isn't so bad, as it already gives us LED control >> (*1), but I don't see any portable way for finding the corresponding >> LED for some input device. In DRM I see the backlight as subdevice. > > With USB-HID keyboards the LED class device will have the same HID-device > as parent as the input device. If there is no HID parent-device, then any > foo_kbd_backlight device will belong to the atkbd (PS/2) input-device. Still a lot of if's and guessing :( Why can't we make it appear the same way like the other leds (eg. caps- lock) ? Here's how it looks on my Portege: | ~ ls -l /dev/input/input0: | | drwxr-xr-x 2 root root 0 Jun 22 11:42 capabilities | lrwxrwxrwx 1 root root 0 Jun 22 11:42 device -> ../../../serio0 | drwxr-xr-x 3 root root 0 Jun 22 11:42 event0 | drwxr-xr-x 2 root root 0 Jun 22 11:42 id | drwxr-xr-x 3 root root 0 Jun 22 11:37 input0::capslock | drwxr-xr-x 3 root root 0 Jun 22 11:42 input0::numlock | drwxr-xr-x 3 root root 0 Jun 22 11:42 input0::scrolllock | -r--r--r-- 1 root root 4096 Jun 22 11:42 modalias | -r--r--r-- 1 root root 4096 Jun 22 11:42 name | -r--r--r-- 1 root root 4096 Jun 22 11:42 phys | drwxr-xr-x 2 root root 0 Jun 22 11:42 power | -r--r--r-- 1 root root 4096 Jun 22 11:42 properties | lrwxrwxrwx 1 root root 0 Jun 22 11:42 subsystem -> ../../../../../../class/input | -rw-r--r-- 1 root root 4096 Jun 22 11:42 uevent | -r--r--r-- 1 root root 4096 Jun 22 11:42 uniq I'd imagine also having some "input0::backlight" here. These leds seem to be sub-devices of the keyboard device, that's perhaps tricky to do with the current backlight drivers - but maybe just add some symlink to it ? --mtx -- --- Hinweis: unverschlüsselte E-Mails können leicht abgehört und manipuliert werden ! Für eine vertrauliche Kommunikation senden Sie bitte ihren GPG/PGP-Schlüssel zu. --- Enrico Weigelt, metux IT consult Free software and Linux embedded engineering info@xxxxxxxxx -- +49-151-27565287
