> >What about simply "echo 0.001 > delay_on"? > This is possible. > But please consider the following reservations: > - There is already 2 files, so you are not going to write settings > atomically anyway. When resolution changes, it might be better > to just reset to the sane defaults (not in my current patch). Sane defaults would be mandatory, but lets get reasonable interface. Someone left 1 in delay_on. You want 100 nsec. You echo nsec > delay_on_units, bang, dead machine, looping in kernel. Someone left 100 / nsec in delay on. You want one usec. Echo 1 > delay_on, bang, dead machine. > - As was already discussed in the same thread, not all drivers > can support sub-ms delays. For these drivers such resolutions > should not be available. With separate file this is naturally > achieved: you either don't create it at all, or list only the possible > resolutions. With your approach you never know whether you > can write 0.0001 or not. Well, so you get back einval. Knowing "unit" is not enough to know how short delays hw can support. > - You will set the delay in ms units. For example for 100us you'll > write 0.1. IMHO it is counter-intuitive: people will make a mistake > and try 0.0001 instead, wrongly assuming that this is in seconds. > And nanoseconds should then better be removed, as writing > nanosecond delay will just require too much zeros. This is machine-to-machine interface. And users can handle this. 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-leds" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
