Messages in this thread | | | Date | Thu, 21 Aug 2003 02:36:29 +0100 | From | Jamie Lokier <> | Subject | Re: Input issues - key down with no key up |
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Andries Brouwer wrote: > There are many more problems with your synthesized events. > Look at your "repeat delay + a bit more". Can you specify how much > "a bit more" is? > > In times of heavy disk activity we lose interrupts. > Indeed, if I copy a CD image or untar a kernel tree > my keyboard and mouse are dead for several seconds. > > There is no guaranteed "a bit more" within which we will see a > keyboard event.
I think we can safely arrange that if the timer expires, we can be sure to check the 8042 for an event before synthesising one.
> If the only events that are seen are actual events, and on rare > occasions we miss an event, that is not so bad. We just hit that > key again. But if we synthesize events, then a missed key up > causes autorepeat.
You've mixed the question synthetic UP with software autorepeat. They are unrelated, and othogonal.
If you use software autorepeat, you have that problem of runaway events _anyway_, nothing to do with UP. And if you don't use software autorepeat, UP doesn't create a problem.
In fact, the synthetic UP is quite helpful if you miss real events. For programs which, say, grab the keyboard focus until the user lets go of a particular key, it is good that the program is eventually sent an UP. Otherwise it won't give up the focus at all. Similarly, in a game which does something as long as the player holds a key down, missing the real event results in the game assuming the key is perpetually held down.
> In fact I see unwanted autorepeat - maybe once a day > suddenly a single keystroke causes three to five identical characters to appear - but I am not sure what mechanism causes this.
Faulty laptop keyboards. I get it too, with 2.4 and 2.5 kernels. It's not autorepeat, it's an instant burst of events. Possibly bad debouncing.
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