Back to home page

DOS ain't dead

Forum index page

Log in | Register

Back to the board
Thread view  Mix view  Order
RayeR(R)

Homepage

CZ,
20.12.2018, 02:20
 

Serious bug in newer nVidia cards VESA VBE (Users)

Hi, I just tested one GTX 670 and found strange flickering in Build based games and Quake too (https://www.youtube.com/watch?v=TV6EAeP8sI8).
This issue is spreaded to wider range of nvidia families at least 6xx to 9xx.
The problem is !nvest!gated (WTF, why is "inv3stigated" marked as bad word I cannot post?) here on VOGONS https://www.vogons.org/viewtopic.php?f=63&t=57420
It was found the bug is in VBE func. 07 for scrolling/page flipping. For Quake there's easy fix to disable page flipping by "vid_nopageflip 1" command entered in console. But for Build engine based games we don't know.
We also need to discover what all families are affected. Until GT2xx within it's OK. We need to test 4xx and 5xx and then latest 1xxx and 2xxx. So please if you have such card share test results.

---
DOS gives me freedom to unlimited HW access.

Laaca(R)

Homepage

Czech republic,
22.12.2018, 21:14

@ RayeR

Serious bug in newer nVidia cards VESA VBE

It is a bit problematic for us to test it. Who from us, DOS fans, has such superb graphic cards?
Is possible to create a image of boot CD with automated and simple test utility? Such test could be acceptable even for non-DOSfanatics.

---
DOS-u-akbar!

rr(R)

Homepage E-mail

Berlin, Germany,
23.12.2018, 22:50

@ RayeR

Serious bug in newer nVidia cards VESA VBE

> The problem is !nvest!gated (WTF, why is "inv3stigated" marked as bad word
> I cannot post?) here on VOGONS
> https://www.vogons.org/viewtopic.php?f=63&t=57420

Because I'm getting a lot of spam mails via this forum and I'm still inv!stigating the issue.
Sorry for any causing trouble to you.

RayeR(R)

Homepage

CZ,
24.12.2018, 15:49

@ Laaca

Serious bug in newer nVidia cards VESA VBE

> It is a bit problematic for us to test it. Who from us, DOS fans, has such
> superb graphic cards?

It's not a highend, Kepler is 6 year old architecture. I just wrote it here because some DOS users may also have access to decent modern HW. Never mind, I got some more info that helped to localize problem. It seems that the VBE bug was introduced in video BIOS major version line 80.x while 70.x is OK. I also got runtime ROM dumps of both versions (where 70.x is confirmed as flicker-free by the user) so I can DASM them and compare. I think I have enough info but it's just time consumnig...

---
DOS gives me freedom to unlimited HW access.

RayeR(R)

Homepage

CZ,
27.12.2018, 17:09

@ RayeR

Serious bug in newer nVidia cards VESA VBE - wokaround TSR!

We was able to make a workaround for buggy nVidia BIOS.
After consulting with Falcosoft user he was kind to wrote a small TSR that changes number of video pages returned by VBE func 01h. This enforces the affected games to not use HW page flipping and use copy buffer instead. Works fine with Quake, Blood, Duke 3D :) Of course I will try to make permanent BIOS mod if I find it in DASM...

---
DOS gives me freedom to unlimited HW access.

Back to the board
Thread view  Mix view  Order
15817 Postings in 1453 Threads, 262 registered users, 9 users online (0 registered, 9 guests)
DOS ain't dead | Admin contact
RSS Feed
powered by my little forum