Re: Serial and pread

[Izak Burger]

Hello,

Me again.

Here is a patch that makes it work.  I'm probably doing something 
terrible here, but it solves the problem for now.  I'm piggy-backing on 
the code for handling FD_TYPE_SOCKET, because I noticed that if I treat 
a serial port with:

ReadIntervalTimeout=MAXDWORD
ReadTotalTimeoutMultiplier=0
ReadTotalTimeoutConstant=0

as a socket it will do exactly what I expect.  If there is another 
better way to do it, please do tell :-)  In my opinion, the problem is 
that the decision as to whether to set the state to STATUS_PENDING or 
STATUS_SUCCESS happens while file io is being done, and the information 
needed to make the decision requires that you know something about the 
serial device while doing file_io.

I can now communicate with the POS, but the app still crashes and dumps 
me in the debugger when it exits.  I don't really care about that though :-)

regards,
Izak

Izak Burger wrote:
> Nope, now the app just dies with very little trace as to why.  Not to 
> worry, I just need to go eat some lunch or something and get my head 
> clear.  This conversation has given me a much clearer understanding of 
> what goes on.
>
> Mike McCormack wrote:
> > Izak Burger wrote:
> > > Ok.  I had to set +comm to get that info, and modified the code to 
> > > dump the contents of the COMMTIMEOUTS structure:
> > >
> > > trace:comm:SetCommTimeouts ReadIntervalTimeout=4294967295
> > > trace:comm:SetCommTimeouts ReadTotalTimeoutMultiplier=0
> > > trace:comm:SetCommTimeouts ReadTotalTimeoutConstant=0
> > > trace:comm:SetCommTimeouts WriteTotalTimeoutMultiplier=0
> > > trace:comm:SetCommTimeouts WriteTotalTimeoutConstant=5000
> > >
> > > MSDN says this means to return immediately with whatever is there.
> > > > ReadFile command may also be important - check whether it is being 
> > > > called with an overlapped structure or not.
> > >
> > > It is called with an overlapped structure:
> > > trace:file:ReadFile 0x88 0x42295ff1 1040 0x4081ace0 0x42295b5f
> >
> > Hi Izak,
> >
> > It appears we don't handle this case properly.  We only handle 
> > ReadIntervalTimeout=MAXDWORD in non-overlapped mode.  Can you try the 
> > following (untested) patch and see if it fixes the problem?
> >
> > Mike
> > Index: server/serial.c
> >
> > RCS file: /home/wine/wine/server/serial.c,v
> > retrieving revision 1.33
> > diff -u -r1.33 serial.c
> > --- server/serial.c    8 Apr 2004 19:09:04 -0000    1.33
> > +++ server/serial.c    14 Apr 2004 10:25:45 -0000
> > @@ -273,6 +273,28 @@
> >          if ( !async )
> >              return;
> > -
> >    /*
> > -
> >     * The following combination of timeout values means we're 
> >
> > try to
> > -
> >     * read as much data as is available, then return immediately.
> > -
> >     */
> > -
> >    if ( (serial->readinterval == MAXDWORD) &&
> > -
> >          (serial->readmult == 0) && (serial->readconst == 0) )
> > -
> >    {
> > -
> >        struct pollfd pfd;
> > -
> > -
> >        pfd.fd = get_unix_fd(fd);
> > -
> >        pfd.events = POLLIN;
> > -
> >        pfd.revents = 0;
> > -
> >        poll( &pfd, 1, 0 );
> > -
> > -
> >        if ( !(pfd.revents & POLLIN) )
> > -
> >        {
> > -
> >            async_notify( async, STATUS_SUCCESS);
> > -
> >            destroy_async( async );
> > -
> >            return;
> > -
> >        }
> > -
> >    }
> > -
> >    async->status = STATUS_PENDING;
> >    if(!async->q)
> >    {

--- wine.old/server/serial.c	2004-04-08 21:09:04.000000000 +0200
+++ wine/server/serial.c	2004-04-21 11:08:12.000000000 +0200
@@ -213,6 +213,18 @@
               (serial->readmult == 0) && (serial->readconst == 0)) )
         *flags |= FD_FLAG_TIMEOUT;

+    /* MSDN says: A value of MAXDWORD, combined with zero values for both the
+     * ReadTotalTimeoutConstant and ReadTotalTimeoutMultiplier members,
+     * specifies that the read operation is to return immediately with the
+     * characters that have already been received, even if no characters have
+     * been received.  
+     *
+     * This will happen if we treat the serial device as if it
+     * is a socket*/
+    if ( (serial->readinterval == MAXDWORD) &&
+        (serial->readmult == 0) && (serial->readconst == 0) ){
+        return FD_TYPE_SOCKET;
+    }
     return FD_TYPE_DEFAULT;
 }