Messages in this thread | | | From | Oliver Neukum <> | Subject | Re: Is it useful to support user level drivers | Date | Thu, 21 Jun 2001 17:19:06 +0200 |
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On Thursday, 21. June 2001 16:46, Dmitry A. Fedorov wrote: > On Thu, 21 Jun 2001, Oliver Neukum wrote: > > > Lastly an IRQ kernel module can disable_irq() from interrupt handler > > > and enable it again only on explicit acknowledge from user. > > > > Unless you need that interrupt to be enabled to deliver the signal or let > > Need not. Signal and other event delivery mechanisms has nothing > common with disable/enable_irq().
And how do you ensure that no interrupt is lost ? In fact you now are likely to have a race condition reading device status or the like.
> > userspace reenable the interrupt. > > "user acknowledge" is mean that. > > > In addition, how do you handle shared interrupts ? > > It is impossible, see my another message.
Which IMHO makes the concept pretty much useless. Interrupt sharing is pretty much the norm today. And there is no evidence for this to change in the near future. Rather the opposite seems to happen in fact.
Which devices were you thinking of, that need a hardware IRQ and no kernel driver ?
Regards Oliver - 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/
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