----- Original Message -----
From: Calin A. Culianu <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, September 29, 2001 9:24 PM
Subject: Re: [rtl] RT-Linux patch proposal for RTF size
queryage
>
>
> On Fri, 28 Sep 2001, Victor Yodaiken wrote:
>
> > You're welcome to send a patch and your tone is fine,
but ...
> > 1. Stuart is right, it's easy, just put the function in
the rtl_fifos code
> I am not sure what you are referring to... if you are
saying that
> creating a custom function to return fifo size is easy,
then yes, I agree
> with that one.. :)
> > 2. I hate adding functions so my question is always
"why do you have to have it"?
> Well, because. :) No seriously I think it's a fair
feature of a fifo
> for one to be able to query its size and/or fill.
In a uniprocessor situation it's only useful if you can
guarantee that no other (real-time) task or ISR will gain
control of the CPU between the query and whatever you
decide to do as a result of it; yes, there can be a
significant number of cases where this guarantee is
(almost)absolute, but as a general rule without disabling
interrupts -- which is depricated in any real-time
system -- it's not particularly useful.
In a SMP system, as a general rule, it's useless.
Norm
>Also, I am being
> particularly anal with respect to my rt-task talking to
userland and I
> want to be absolutely sure that I don't have any failed
and/or partial
> writes.. the only way to really accomplish this is to
have the ability to
> query the fifo size/freeness. I don't *absolutely* need
this feature, but
> if would make me happy if this feature were included. :)
>
> -Calin
>
>
> >
> >
> > On Fri, Sep 28, 2001 at 04:21:45PM -0400, Calin A.
Culianu wrote:
> > >
> > > I realize the tone of my previous this email seems
impatient.. it isn't.
> > > Actually if you guys would honor me with your
approval, I can gladly
> > > submit a patch that defines an interface for my
proposed solution (a)
> > > below, or one that moves the struct definition of
struct rtl_fifo_struct
> > > over to the more public 'rtl_fifo.h' header file.
(Since the kernel symbol
> > > rtl_fifos is already exported).
> > >
> > >
> > > Please allow me to be an rt-linux developer!! :)
> > >
> > > -Calin
> > >
> > > ---------- Forwarded message ----------
> > > Date: Fri, 28 Sep 2001 15:35:38 -0400 (EDT)
> > > From: Calin A. Culianu <[EMAIL PROTECTED]>
> > > To: [EMAIL PROTECTED]
> > > Cc: rtl <[EMAIL PROTECTED]>
> > > Subject: RE: [rtl] number of elements in a fifo
> > >
> > > Well, in kernel mode there's no way to tell how full
a fifo is (as of rtl
> > > 3.1)!
> > >
> > > Actually, that macro only occurs in rtl_fifo.c, and
furthermore, the
> > > exported kernel symbol "rtl_fifos" that the macro
really uses is of
> > > type struct rt_fifo_struct, which is a private type
inside rtl_fifo.c!
> > >
> > > Why is kernel symbol 'rtl_fifos' exported when its
type is private?
> > > It aggravates me!!
> > >
> > > Can someone on the rt-linux dev team either kindly:
> > >
> > > a) create a public interface to find out the size
and/or the bytes free in
> > > an rtf (this is trivial, just make a function that
returns
> > > rtl_fifos[minor].bufsize, rtl_fifos[minor].len etc).
> > >
> > > OR
> > >
> > > b) make struct rtl_fifo_struct a public struct????
(since the array of
> > > fifos is exported into the kernel symbol table
anyway).
> > >
> > > -Calin
> > >
> > > On Fri, 21 Sep 2001, stuart warren wrote:
> > >
> > > > To read how full the fifo is from userspace...
> > > >
> > > > int bytes_in_fifo;
> > > > ioctl(rtfifo_fd, FIONREAD, &bytes_in_fifo);
> > > >
> > > > In the kernel you can use...
> > > >
> > > > bytes_in_fifo = RTF_LEN(fifo_number);
> > > >
> > > > Cheers,
> > > > Stuart
> > > >
> > > > -----Original Message-----
> > > > From: fred august [mailto:[EMAIL PROTECTED]]
> > > > Sent: Thursday, 20 September 2001 6:00
> > > > To: rtl
> > > > Subject: [rtl] number of elements in a fifo
> > > >
> > > >
> > > > Hi,
> > > > is there a simple way to know how many
elements
> > > > are in a FIFO? This should be in RT, or almost, for
a
> > > > FIFO between a RT thread and a user space one. I
need
> > > > this information in order to dump some of the
elements
> > > > if the FIFO is too full.
> > > >
> > > > thanks
> > > >
> > > > f
> > > >
> > > >
___________________________________________________________
___________
> > > > Do You Yahoo!?
> > > > Il tuo indirizzo gratis e per sempre @yahoo.it su
http://mail.yahoo.it
> > > >
> > > > -- [rtl] ---
> > > > To unsubscribe:
> > > > echo "unsubscribe rtl" | mail [EMAIL PROTECTED]
OR
> > > > echo "unsubscribe rtl <Your_email>" | mail
[EMAIL PROTECTED]
> > > > --
> > > > For more information on Real-Time Linux see:
> > > > http://www.rtlinux.org/
> > > >
> > > > -- [rtl] ---
> > > > To unsubscribe:
> > > > echo "unsubscribe rtl" | mail [EMAIL PROTECTED]
OR
> > > > echo "unsubscribe rtl <Your_email>" | mail
[EMAIL PROTECTED]
> > > > --
> > > > For more information on Real-Time Linux see:
> > > > http://www.rtlinux.org/
> > > >
> > >
> > >
> > > -- [rtl] ---
> > > To unsubscribe:
> > > echo "unsubscribe rtl" | mail [EMAIL PROTECTED]
OR
> > > echo "unsubscribe rtl <Your_email>" | mail
[EMAIL PROTECTED]
> > > --
> > > For more information on Real-Time Linux see:
> > > http://www.rtlinux.org/
> >
> > -- [rtl] ---
> > To unsubscribe:
> > echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
> > echo "unsubscribe rtl <Your_email>" | mail
[EMAIL PROTECTED]
> > --
> > For more information on Real-Time Linux see:
> > http://www.rtlinux.org/
> >
>
> -- [rtl] ---
> To unsubscribe:
> echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
> echo "unsubscribe rtl <Your_email>" | mail
[EMAIL PROTECTED]
> --
> For more information on Real-Time Linux see:
> http://www.rtlinux.org/
>
-- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
--
For more information on Real-Time Linux see:
http://www.rtlinux.org/
