Date: Tue, 27 Oct 1998 12:09:58 -0800 From: Mike Smith <mike@smith.net.au> To: Christopher Masto <chris@netmonger.net> Cc: hackers@FreeBSD.ORG Subject: Re: Some curiosity about syscons Message-ID: <199810272009.MAA00912@dingo.cdrom.com> In-Reply-To: Your message of "Mon, 26 Oct 1998 23:02:08 EST." <19981026230208.A8159@netmonger.net>
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> Anyway.. I wasn't quite sure what the best approach would be, so I > decided to see if I would just luck out and need no more than stdio > and some cheating. It turns out, of course, that syscons doesn't > simply put what you send it on the screen; it puts it into a buffer > which is copied to the screen periodically, so I couldn't trivially > make it work. > > Rather than back up and start over with a different approach, I added > a tiny ioctl to syscons to call scrn_update(). With that and some > fudging, I actually have the damned thing working. You could just have memory-mapped the display buffer, of course. 8) > If anyone is still following this, and particularly if you Know From > Experience, perhaps you can comment on some of these architectural > issues. I need a 60Hz vertical refresh rate, and I need to be able to > display 18 lines of text every frame. This needs to happen during the > vertical retrace interval, as a single glitched frame will cause a > failure. Ideally I would like the cursor not to be present, but it > isn't actually a problem if I can make sure it is always at the top or > bottom of the screen. This *definitely* wants to be done inside the kernel. Use the screensaver interface, add a couple of ioctls (pass data to saver, activate saver) and you're done. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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