Subject: Re: default built kernels and com4
To: None <>
From: Greg Cronau <>
List: current-users
Date: 04/13/1994 14:24:38
Ken Hornstein
>>> For those of us with mach32 based cards, the com4 support makes the default
>>> kernels useless.
>>why?  I don't have a mach32-based card, and am not going to buy one to
>>find out why they don't work with kernels w/com4...
>The mach32 cards use the same I/O address as com4 for some of the card's
>registers (I don't know the exact details).  I happened to discover this by
>accident, as the info is buried in a really obscure spot in the manual.
>The probe and attach routine from 0.9 didn't bother the mach32, but apparantly
>the ones on -current flip different bits, because it makes the card freak out.

Ok, that explains it.
I also have an ATI Graphics Ultra PRO EISA board. It is based on the 
Mach-32 chip. This board worked fine with -0.9, but after I installed the
generic bt kernal from the April-3 binary snapshot, the card stopped
working. Immediately after the "using xxx buffers with yyyyyy memory"
message was printed, the screen would blank. Now what was interesting, is
that the machine would continue booting. I could see disk activity and
would get responses to the keyboard, but the screen would stay blank.

I pulled the ATI card and put in a Really-Stupid-and-Cheap-$25 vga board
and the problem went away. I continued installing the 04-06 current source at
this point. After *all* the new stuff had been installed and I had rebuilt
everything and had built myself a new kernal, I decide to reinstalled the
ATI card to see if somebody had fixed the problem in the newer code I had.
The card worked at this point.

I had built my kernal without the comm 3 and 4 drivers because:
1.) I didn't need them and
2.) com4 was set up for interupt 9 and I use that interupt for my ethernet.
Apparently commenting out com3 and com4 was what also got my ATI card

I would also like to suggest that com3 and com4 should be removed from the
GENERIC kernal. I know one of the Netbsd development machines uses com3 and
com4 but isn't the purpose of a "generic" kernal to:
1.) Come up on as many machines as possible without conflicts and
2.) to provide just enough resources to allow someone to build their own
    kernal customized to thier own setup.
Removing com3 and com4 from the GENERIC kernal would further #1 without
adversely impacting #2.

Greg Cronau