Exactly, This is what i wanted to do. So i was thinking of User space call
from the driver through a function pointer. (my first mail)
On 4/9/07, priv < wdm.8723083@xxxxxxxxxxx> wrote:
> It depends what you want to achieve. In any aspects, polling is not a
> good idea for driver anyway.
>
> You may want to send a message from driver when something in driver
> occurs, and setup your application to listen that message. After
> user-mode application receive the message, then you can call your
> function in the user space and/or use IOCTL for what you really want
> to do.
>
> On 4/9/07, AsHwAtH <itsmeash@xxxxxxxxx> wrote:
> > Ok, Thank you for the suggestion.
> >
> > But how are callbacks really implemented then?
> > If I keep calling DeviceIOControl from my application(like polling), it
> > drains CPU usage.
> >
> >
> >
> >
> > On 4/9/07, Eugene Muzychenko < emuzychenko@xxxxxxxxx> wrote:
> > > Hello AsHwAtH,
> > >
> > > > From my application I am passing the address of the User defined
> > function to
> > > > the driver through my own IOCTL call.
> > > > I store this address in the driver as a function pointer and call it
> > when a
> > > > particular condition is met inside the MSVAD.
> > >
> > > Before trying to develop (and even modify) a kernel-mode driver, you
> > > must clearly understand the differences between user and kernel
> > > execution modes, address space, thread contexts etc. Your attempt to
> > > directly call a user-mode function from the kernel-mode driver means
> > > that you have almost no such knowledge. In this situation, your work
> > > will be very inefficient, resulting many incorrect solutions.
> > >
> > > Your driver could inject some code into a requesting
> > > process, create an auxiliary thread that will watch for some event
> > > signaled by the driver and call a specified function. But it will be
> > > very complex for you to implement. So a simplest way is to create a
> > > thread from your application and not to pass function address to the
> > > driver.
> > >
> > > Regards,
> > > Eugene
> > >
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