Hi! > > Yes, Morse code can indicate any means. But when we look at the LEDs, would we like to also have a Morse code book in hand? > > > > The burst led blink idea is because it is easy to use and easy to describe. Mostly when users on site are describing the LEDs states to the support engineer. > > Sure but > - Why bother putting it into the kernel when you can do it in user > space At least nokia N900 actually has "hardware acceleration" for LED blinking. (Tiny CPU connected over i2c, able to control 3 LEDs, turing complete with something like 20 _bits_ of storage and 30 program steps). Apparently, it makes more stable patterns (timing is very hard to guarantee from userspace) and better power consumption (no need to wake the CPU to blink the LEDs). Now, wins from going userspace->kernel will not be too huge. But "If the hardware can accelerate it, kernel should offer it even on hardware that can not do it, for consistency". [Ok, I should mention that N900 can actually do 3-colored LED with PWM and synchronization between the colors -- so it can do smooth power ramp ups. Proposed interface does not cover that. Actually even better interface might be: integer: time in msec for each step pattern: binary string, with each u8 being intensity in 0-255 range That would cover N900 features that are easy to emulate while being practical to do on machines that do not have hardware acceleration for LEDs. But it still does not cover synchronization between the three RGB channels :-(.] > - Why use morse code when you are probably better using something that > can be decoded in software off a phone video and so has FEC (viterbi or > similar) on it ? I'd say decoding "3 blinks" -- dishwasher lacks water is easier than pulling than installing decoding app on a phone. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
