Messages in this thread | | | Date | Thu, 21 Jun 2001 19:45:51 +0700 | From | "Dmitry A. Fedorov" <> | Subject | Re: Is it useful to support user level drivers |
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On Thu, 21 Jun 2001, Alan Cox wrote:
> > it would be a good idea to add user level interrupt > > support ? I have a framework for it, but it still > > The problem is that the IRQ has to be cleared in kernel space, because otherwise > you may deadlock.
It depends on device type. Good designed ones does not raises a new interrupt until an explicit acknowledge by I/O from [user space] driver will be received.
Access to device's ports and IRQs from user space is subject of system admistration policy so direct access to a dangerous devices should not be allowed.
Lastly an IRQ kernel module can disable_irq() from interrupt handler and enable it again only on explicit acknowledge from user.
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