Subject: Re: Screen blanking
To: Trevin Beattie <email@example.com>
From: Ken Hornstein <firstname.lastname@example.org>
Date: 06/07/1996 11:37:39
>OK, I've got only one more minor annoyance with the kernel now. Ever since
>the March sources (and up to May 25), whenever I boot the kernel I can see
>it load the /netbsd file and then a few lines of devices before the screen
>turns completely black. Fortunately I have xdm in my rc.local file;
>otherwise this would be a major problem rather than just an annoyance. X
>eventually shows up, and when I shutdown the computer the text screen
>reappears with the last screen from boot time.
>Any ideas? I'm using the pccons driver, i386 architecture, and a mach32
Do you have a com3 in your kernel config file?
It turns out that the ATI cards emulate an 8514 (I think) video card. It
turns out that some of the registers in that card cross over with the port
range used by com3 (COM4 in DOS). _And_ it so happens that the probe routine
for the com port frobs some registers on the video card that end up making
the screem completely blank.
This issue was talked about a lot right before the 1.1 release -- eventually
it was decided not to put a com3 in the installation kernels. I don't
think that has changed.