Messages in this thread | | | Date | Wed, 30 Jul 2003 19:50:04 +0100 | From | John Bradford <> | Subject | Re: PATCH : LEDs - possibly the most pointless kernel subsystem ever |
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> > > But this kind of blinkenlights needed pretty fast LEDs. (At 486 time > > > I decided that parport on ISA is fast enough..) > > > > I'll buy some LEDs and build a parallel port connected LED panel > > tomorrow... Do you think the overhead of driving the LEDs would have > > too much of a negative effect on system performance? If so, or if > > we > > I'm not sure. At 486 days I was pretty sure it did not matter. These > days you might get 10% slowdown on some microbenchmark, or something > like that. I do not think it can slow down common tasks.
OK, so no problems there...
> My construction of LED lights is extremely flaky, and I'm afraid of > burning printer port. At 486 days ports were expected to survive such > abuse. Not sure if todays EPP/wtf ports can handle that.
This could be a problem, though - now I've looked in to it, the maximum recommended current drain on the parallel port seems to be really low :-(.
I've CC'ed Alan - maybe he can offer some advice.
(Alan - basically we're thinking of using this LED-on-parallel-port driver for a standardised 'front panel', showing things like interrupt being serviced, BKL taken, etc, for debugging purposes.)
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