On Fri, 15 Oct 2004 16:15:42 -0400, Robert Love <rml@xxxxxxxxxx> wrote: Perfect Stranger> > 3- how can disabled interrupts be unlost ?? > No, they are not lost. They are queued in the interrupt controller and > they pop when you re-enable interrupts. > > The only issue is that you only get one interrupt per-line, even if n>1 > were queued on that line. This is almost never a problem, except with > the timer interrupt. There is also an issue which arises out of the different types of interrupt triggering used. However this is almost certainly not an aspect of your original question. When a device signals an interrupt, it does so in every case I know of by signalling a voltage on a particular bus line, and this can vary in implementation - rising edge transition from low to high voltage value, falling edge transition from high to low voltage value, or level triggering based upon a threshold voltage for high and low. In the case of edge triggering however (and this is anal and pedantic of me to mention it here), it's possible to miss an edge interrupt that comes in while we're handling another - but it might be possible to figure out that we missed one. So there's just a chance you've been looking at some weird PIC code to try to detect this, but it's unlikely so I won't try delving further right now. Jon. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
