![]() | ||||||||||
Messages in this thread |
> > I have a very basic doubt here ... what makes it impossible to sleep > > in an ISR? I mean, I know that the kernel preemption is disabled and > > the kernel will panic, but I could not understand why? > > Because the interrupt which you are serving in the > ISR has been masked to avoid preemption( > true for maskable inetrrupts ).Any locks you are holding in ISR are now with > you solely. So, if you try to sleep you take the locks you untill you are > rescheduled and complete. This may lead to > a deadlock for the lock resource. Ok, but how about an ISR, that does not take any locks? Why can't we sleep in SUCH an ISR? AFAIK, taking a lock disables kernel preemption, and hence it is not allowed to sleep. So I think my question would boil down to why is sleeping not allowed when the kernel preemption is disabled. LL - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
| Last update: 2007-05-14 07:19 [from the cache] ©2003-2008 | ||||||||||