keyboard loss in DF

Michael Powell nightrecon at hotmail.com
Mon Dec 13 02:29:14 PST 2004


Michael Powell wrote:

> [snip]
> Jeroen Ruigrok/asmodai wrote:
> 
>> When you ssh/telnet in, and run systat -vmstat look at the right column
>> of irqs, hit the keys on the keyboard, does it generate interrupts?
> 
> Next time I move things around (probably later this afternoon) I'll look.
> 
> I did a vmstat -i, but, of course, it was showing 0 in the Rate column 
> because the kbd was already gone. 
> 
[snip]

The systat -vmstat shows the same. I get interrupt activity until the
keyboard disappears, then it drops to 0 and that's that.

The one thing I was curious about because I don't remember whether every
keypress is supposed to generate a unique interrupt, or whether the irq
occurs upon pressing the Enter key or/and the 10 byte buffer filling. 

What I was doing was pressing the Numlock key and counting. If each keypress
generates its own irq it looks like some irqs are getting dropped before
the keyboard goes away completely. Because of the sampling period there is
a skew, but it seems as if what I count doesn't match the total. Which may
be perfectly fine, depending upon the above.

-Mike






More information about the Bugs mailing list