lkml.org 
[lkml]   [2001]   [Jun]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Is it useful to support user level drivers
    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.

    -
    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: 2005-03-22 12:55    [W:0.023 / U:30.004 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site