Date: Fri, 02 Mar 2001 18:02:56 +0300 (MSK) From: Dmitry Dicky <diwil@eis.ru> To: freebsd-hackers@freebsd.org Subject: stupid device driver question Message-ID: <XFMail.010302180256.diwil@eis.ru>
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Hi fellows,
I'm writing some device driver which should pass some data to the user
space.
The part of the device read routine looks as follows:
----------------------------------
int
dev_read(dev_t dev, struct uio *uio, int ioflag)
{
int err = 0;
/* ... */
amnt = MIN(uio->uio_resid, cntw);
/* Wait here until data available .... how? */
err = uiomove(buf2, amnt, uio);
if (err != 0) {
return(err);
}
memset(buf2, 0, amnt);
cntw -= amnt;
return 0;
}
-------------------------------------
User application hands on read(2).
But buf2 being filled upon some event and 'dev_read' should
wait until data in buf2 available.
So, the question is:
How can I hang dev_read, issue some signal and then continue uiomove(9)
data to the user space?
Thanks in advance,
D.
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