Re: AW: AW: Accessing the tty structure of an opened device
In message 10553.972652114@critter Poul-Henning Kamp writes: : the time between a pulse and a space often only takes : a few milliseconds. I have to meassure that with : gettimeofday(). : : You will need to do this in a device driver, there is no way you : can reliably measure that from userland. : : Trust me on this: I've tried. We at timing solutions had a heck of a time measuring timing things in userland and it became very easy to do it in kernel land. We used the parallel port to measure out pulses, but the same pps api that Poul should work for the serial port as well. And the advantage of the pps api is that it queues up events (iirc) and counts them so you know if the buffer overflowed and you missed any. Warner To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: AW: AW: Accessing the tty structure of an opened device
In message [EMAIL PROTECTED], Warner Losh writes: And the advantage of the pps api is that it queues up events (iirc) and counts them so you know if the buffer overflowed and you missed any. Sorry: not it doesn't. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
AW: AW: Accessing the tty structure of an opened device
From: Poul-Henning Kamp [mailto:[EMAIL PROTECTED]] Subject: Re: AW: Accessing the tty structure of an opened device How fast do these pulses arrive ? Consider using the PPS-API for that: sys/timepps.h the time between a pulse and a space often only takes a few milliseconds. I have to meassure that with gettimeofday(). Greetings, Alex To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: AW: AW: Accessing the tty structure of an opened device
In message [EMAIL PROTECTED], Alexa nder Maret writes: From: Poul-Henning Kamp [mailto:[EMAIL PROTECTED]] Subject: Re: AW: Accessing the tty structure of an opened device How fast do these pulses arrive ? Consider using the PPS-API for that: sys/timepps.h the time between a pulse and a space often only takes a few milliseconds. I have to meassure that with gettimeofday(). You will need to do this in a device driver, there is no way you can reliably measure that from userland. Trust me on this: I've tried. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
