Date: Wed, 14 Feb 1996 20:23:27 +1030 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: hackers@freebsd.org Subject: care and feeding of selwakeup() ? Message-ID: <199602140953.UAA16773@genesis.atrad.adelaide.edu.au>
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Hiho all you device-driver people again; yet another question to bore you
senseless. (Eric, are you keeping track of all these answers? 8)
I have a device select function that (appears) to be happily registering
a selector on my device (only one, but that's fine). eg:
if (rw == FREAD) /* selecting to read */
{
if (rxbuflen(md)) /* data available to read */
{
splx(s);
return(1);
}
selrecord(p,&(md->rsel));
splx(s);
return(0);
}
I can tracewrite and see that this is called OK, and the process selecting
waits on 'select', so all appears OK there.
Now my interrupt handler comes along, receives some data and wants to
kick any selector into action :
if (readsome) /* anything in? */
{
debug("kick read selector (pid %d)",md->rsel.si_pid);
selwakeup(&md->rsel);
md->rsel.si_pid = 0;
md->rsel.si_flags = 0;
...
}
But select in the reader never comes back (though the pid's match).
Any magic ideas? I'm stumped...
--
]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[
]] Genesis Software genesis@atrad.adelaide.edu.au [[
]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[
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]] Collector of old Unix hardware. "I seek PEZ!" - The Tick [[
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