Date: Sun, 30 Sep 2001 14:30:18 -0500 From: Mike Meyer <mwm@mired.org> To: Bart Kus <bsd@shell-server.com> Cc: hackers@freebsd.org Subject: Re: sio modification Message-ID: <15287.29386.998663.37631@guru.mired.org> In-Reply-To: <200109301003.06903@EO> References: <200109301003.06903@EO>
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Bart Kus <bsd@shell-server.com> types: > manipulates the CD line of the serial port it plugs into. Afaik, the UART > itself is capable of generating an interrupt whenever CD changes. The > problem is, sio.c doesn't support this feature. I'm stuck with polling the > status register to find out the state of CD. Not a very good solution for a > daemon that's supposed to run in the background all the time, especially > since the CD line will be toggled at about 40kHz (I think that's the remote > control frequency standard). Perhaps I'm wrong about the 40kHz figure. It looks like you've already got a solution to this problem, and this won't be very useful if the 40kHz figure is right, but I figured I might mention it anyway. Have you thought about using the feature of the callin device of the "open" call blocking until it gets CD? You should then get a SIGHUP when CD drops. <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/home/mwm/ Q: How do you make the gods laugh? A: Tell them your plans. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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