In article <JCONGER.93May3105
...@magnusug.magnus.acs.ohio-state.edu> jcon
...@magnus.acs.ohio-state.edu (James A Conger II) writes:
> In article <C6F3Aw.
...@cbnewsj.cb.att.com> d
...@cbnewsj.cb.att.com (david.e.wexelblat) writes:
> Define "corrupted". There are two cases that I've heard of:
> 1) The screen has lost sync when you switch back to text mode
> 2) The screen is fine, but the text itself is garbled.
> I had a case of "2" with a 2 year old PerfectView ET4000 card from
> ViewSonic. The ROM copyright message said it was some sort of STB card.
> Also, I had problems with 1024x768 mode in X and in Windows: pixels
> would get randomly "left behind" when I moved a window.
> I called ViewSonic and complained politely. They just as politely sent
> me a free ROM upgrade. I now have v5.1 instead of v1.0 ROMS and the
> copyright message now says I have an STB ERGO card. The text mode problem
> "2" is gone and the random pixel problems seem to be gone, too.
> Try your dealers/manufacturers. New ROMs might help.
> Jim
> --
> James A. Conger II |jcon...@magnus.acs.ohio-state.edu (personal)
> Electrical Engineering Student|con...@cis.ohio-state.edu, osu-cis!conger (work)
> The Ohio State University |con...@nes.nersc.gov (DOE Education Programs)
> |CompuServe: 71213,54 (checked every 1-2 days)
Rabbit droppings (as I call the phenomemnon you describe :->) are almost
exclusively caused by hardware problems. Some things that I have seen that
cause this:
1) Video memory (0xA0000-0xAFFFF) is being cached. Video memory
should NEVER be cached.
2) Bus speed set too high for the video card to handle.
3) Bus speed set too low for the video card to handle (really -
I've had things work fine on an 11Mhz bus, and flake out on
an 8.33Mhz bus).
4) Dot-clock too high for video memory speed. Usually shows up in
cheap boards with 80 or 100ns DRAMs, and the video mode is using
a dot-clock above about 50MHz. A GOOD board should have 70 or
even 60ns DRAMs.
5) Poorly-designed 0-wait-state circuitry. Some boards go bonkers
at high dot-clock settings if the ISA-bus 0-wait-state mode is
enabled (which is usually is). In my experience, this problem
starts out as rabbit-droppings, and as the dot-clock gets higher,
can actually lock up the bus (and thereby hang the system).
In your case, changing the BIOS may have changed some of the timing
parameters between the ET4000 and the video memory, hence resolving the
problem on the bus itself.
This should probably be in the FAQ somewhere.
--
David Wexelblat <d...@mtgzfs3.att.com> (908) 957-5871 Fax: (908) 957-5627
AT&T Bell Laboratories, 200 Laurel Ave - 3F-428, Middletown, NJ 07748
XFree86 requests should be addressed to <xfre...@physics.su.oz.au>
"How many times must good men die? How many tears will the children cry,
'til we suffer no more sadness? Oh, stop the madness. Stop all the madness."
-- Molly Hatchet, Fall Of The Peacemakers.
