[EMAIL PROTECTED] wrote:
>
> On Mon, May 24, 1999 at 10:27:16AM +0000, Paolo Mantegazza wrote:
> > Tomasz Motylewski wrote:
> > >
> > > On Thu, 20 May 1999, Sugat Jain wrote:
> > >
> > > > My problem right now is an implementation one: When a received packet is to
> > > > be handed over to the linux part for processing by higher layers, when a
> > >
> > > Yes, this is the problem to which I knew no satisfactory answer. What is
> > > needed is a "bottom half" for RT interrupt. So, when your RT-ISR sees a
> > > normal packet to be passed through netif_rx it can set some flag and exit.
> > >
> >
> > The problem of bottom hakves can be solved if RTL implemented a feature,
> > available in RTAI, i.e system requests (srq). This a a mechanism which
>
(here something went lost so I add the missing lines, sorry)
allow a user to install a software handler to which he can pend Linux
kernel requests that are treated as a usual interrupt when the kernel
runs. (see the doc at "http://www.aero.polimi.it/projects/rtai/"
> The problem of bottom halves was solved in RTL with the mechanism used by
> fifo handlers -- easily adaptable to other operations.
.... with or without touching the kernel?
> Since V1 we have
> also had the ability for rt irq handlers to pend interrupts for Linux
> handlers.
...... native in RTAI.
> In V2 we will have special "soft interrupts" for RTL to send
> to linux.
......... it is exactly what I called "srq" above.
So I'm very glad to see native RTAI features in RTL.
Now you have just to take away a lot of not needed kernel patching and
put it in an interface module and we can rejoin.
Then I dare to make a further suggestion about another native feature of
RTAI.
Allow RTL to force Linux to share any interrupt even if Linux installed
one non sharable. In that way you permit RTL users to pend interrupts to
a handler of theirs that is called whenever the corresponding Linux
handler is.
Very usefull for monitoring porpuses, debugging RTL applications and a
lot of other usefull things I let you imagine.
RTAI uses this mechanisms to nicely recover lost Linux jiffies, so that,
if there is enough time left by the real time application, Linux can
sooner or later recover its time.
By the way why V1 and V2 have never been announced?
Ciao, Paolo.
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