Hello all,

I've got an Optiplex 745 with a build-in "Intel Q965/Q963 Express Chipset
Family" videocard. On it I've written a OpenGL (3D) program. In certain
circumstances the screen blanks and the 'puter locks up. The same program
on another 'puter runs fine, even though it stutters a bit at the "certain
circumstances" I mentioned (likely an indication of needing a bit more time
to finish drawing the scene).

The only way /not/ to get the black screen and the 'puter locked up is to
pretty-much disable (one step above none) all hardware acceleration for the
videocard.

My question : Does anyone recognise it and knows how to fix it (other than
by keeping the hardware acceleration on a low setting) ?

Again the specs:
Computer : Optiplex 745
Videocard: Intel Q965/Q963 Express Chipset Family

Regards
Rudy Wieser

On 10/7/2022 2:03 PM, R.Wieser wrote:
> Hello all,
>
> I've got an Optiplex 745 with a build-in "Intel Q965/Q963 Express Chipset
> Family" videocard. On it I've written a OpenGL (3D) program. In certain
> circumstances the screen blanks and the 'puter locks up. The same program
> on another 'puter runs fine, even though it stutters a bit at the "certain
> circumstances" I mentioned (likely an indication of needing a bit more time
> to finish drawing the scene).
>
> The only way /not/ to get the black screen and the 'puter locked up is to
> pretty-much disable (one step above none) all hardware acceleration for the
> videocard.
>
> My question : Does anyone recognise it and knows how to fix it (other than
> by keeping the hardware acceleration on a low setting) ?
>
> Again the specs:
> Computer : Optiplex 745
> Videocard: Intel Q965/Q963 Express Chipset Family
>
> Regards
> Rudy Wieser

I would double check the memory allocation for the Q965
in the BIOS, versus the total system memory.

Really, the setup should make safe allocations that
cannot overrun the OS.

There are various schemes for iGPU memory allocation. You can
have a small static allocation suited to compositing. But you
can also have a dynamic allocation (some up to 1536MB setting),
that allows DirectX/OpenGL to chow down on graphics memory.
And this is system memory that is grabbed at runtime
(has the potential to starve the OS and freeze it).

I would revisit the BIOS, and adjust any 1536MB values, to
something more realistic and within range of system memory.
If the machine only has 512MB (WinXP era), then even 128MB
is pushing it on dynamic. You might have to hop down to
the minimum setting available.

There are OpenGL drivers, which lack a working "mem avail"
call in OpenGL. This causes stuff to blow up. LibreOffice
triggered this on my other machine. LibreOffice could not
tell that OpenGL had run out of RAM, and something crashed
as a result of the software failure. I was drawing a graph
in Calc (Excel) and the machine was very busy for five
minutes, before it ran out of RAM. I was not impressed
later, to discover via Google, that programs really could
not tell the graphics RAM had run out.

I would sooner believe a memory issue, than some other
kind of issue. At least, as a starting point in the analysis.

Paul

Hello Paul,

> I would double check the memory allocation for the Q965
> in the BIOS, versus the total system memory.

Alas, when I visited the BIOS I saw no options in that regard anywhere (just
one to use the internal or an add-on video card).

looking at its properties (right-click the desktop and all that) I see it
has 256MB of memory, with no indication of any kind of allocation from
system memory (static or dynamic).

> There are OpenGL drivers, which lack a working "mem avail"
> call in OpenGL.

You're referring to "OpenGL32.DLL" there ? AFAICR its the one that came
with my installation of the OS (XPsp3). And I've just checked, but none of
its functions have "mem" in its name.

> LibreOffice could not tell that OpenGL had run out of RAM, and something
> crashed as a result of the software failure.

In my case I've created a simple static scene (a textured floor, walls and a
cube) and just moved the "camera" around. Nothing dynamic (that I'm aware
of). IOW, if the card would run out of memory I would expect it to crash
in the scene creation or while drawing its first scene.

Also, I've currently have zero idea how the "hardware acceleration" comes
into play.

> I would sooner believe a memory issue, than some other
> kind of issue. At least, as a starting point in the analysis.

Possible, but than I would assume I would, in the past five years, have had
more problems with it. Especially when running stuff like VLC Media player
(which, even on the next-to-lowest "hardware acceleration" setting still
seems to work fine. Chapo.)

Thanks for the suggestions, it gave me a few things to check (amazing how
fast you forget stuff when you don't use it regulary. :-\ )

Regards,
Rudy Wieser