Path: utzoo!attcan!uunet!cs.utexas.edu!chinacat!chip From: chip@chinacat.Unicom.COM (Chip Rosenthal) Newsgroups: comp.unix.sysv386 Subject: quack surgery on a VGA card Message-ID: <1575@chinacat.Unicom.COM> Date: 13 Sep 90 21:42:51 GMT Organization: Unicom Systems Development, Austin, TX Lines: 23 I am running ODT on a Micronics 386/20 with an Orchid Prodesigner running in normal 640x480 VGA mode. This board brings a trace out to the IRQ9/IRQ2 bus pin. I am assuming it's the vertical retrace signal. I further believe that such a signal isn't used by the system, therefore I took an Xacto knife to it to free up that IRQ. Now I am seeing flaky behaviour on the ODT machine. Every once in a while, the display gets scrambled. Things continue running, but it looks like someone took a huge phospher eraser and smudged up the whole screen. Switching to a different mscreen and back cures the problem. I haven't seen this behaviour before. However, there were other changes (such as the installation of a multi-port serial card) at the same time which might be having an effect. It does seem like something is going goofy with the memory system, and I'm wondering if that signal is indeed used after all in a refresh somewhere. Can anybody say definitively whether I made a major goof? I will try reconnecting that trace tonight to see if there is any effect. -- Chip Rosenthal Unicom Systems Development, 512-482-8260 Our motto is: We never say, "But it works with DOS."