Date: Tue, 26 Oct 1999 16:48:52 +0900 From: Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp> To: Mike Nowlin <mike@argos.org> Cc: "Jose M. Alcaide" <jose@we.lc.ehu.es>, freebsd-hardware@freebsd.org, yokota@zodiac.mech.utsunomiya-u.ac.jp Subject: Re: a desirable fetaure: syscons reset utility Message-ID: <199910260748.QAA15139@zodiac.mech.utsunomiya-u.ac.jp> In-Reply-To: Your message of "Tue, 26 Oct 1999 01:52:02 -0400." <Pine.LNX.4.05.9910260149520.30669-100000@jason.argos.org> References: <Pine.LNX.4.05.9910260149520.30669-100000@jason.argos.org>
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>> > The above sequence MIGHT work. But, sadly, it won't, in general. >> > There isn't a reliable way of `resetting' video hardware once the X >> > server has messed up with it. >> > >> >> Oh, bad news. I tried that sequence of commands several times, without >> any luck. Well, we will have to live with this problem. Fortunately, >> my Xserver does not crash very often ;-) . > >I ran into this problem on some Linux boxes - somewhere, I found a program >that saved the video card registers when it was in a "usable" mode (80x25 >text) to a file, and let you restore them later... Basically, if the X >server crashed, telnet into the dead machine, kill X, and use this program >to restore the video card settings. Worked about 90% of the time, I'd >guess. Is something like this available on FreeBSD (or need to be >written?) This won't reliably work, if the said program is saving/restoring only the standard VGA registers. Because the X server touches various extra registers which are not present in the standard VGA, you need to save these registers as well as the standard VGA registers. Restoring only the standard VGA registers is not enough to bring the video card back to known state. When vidcontrol issues the ioctl command to switch the video mode, the vga video driver will set the standard VGA registers to the values listed in the card's BIOS ROM (or use the VESA BIOS to set up the VESA video mode). If the video BIOS cannot set up the card, then, what can we do? Does this Linux utility have some knowledge about extra registers and is able to save and restore them? Kazu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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