we're distributing a program which uses the free allegro library (Version 4.2.3) to present test programs in fullscreen mode. Since the new second generation intel core-i with its processor graphics the output is almost completely blank in fullscreen mode.
The funny thing: Connecting a secound monitor, forcing the driver to switch to dual monitor mode, all works fine...on both displays!
Using the latest drivers isn't possible in all cases (may depend on the update policy of notebook manufacturers e.g.), but at least this problem occurs with all driver versions until 126.96.36.1999.
This strange behavior has been reported from several of our customers, all with devices equipped with second generation intel core-i, even in connection with dedicated graphics from AMD or nvidia.
Anyone seen this before?
In regards to this issue, could you attach some screenshots to the thread?
Also, have are you having problems with any other applications?
If this is happening with various different graphics controllers, we would be more led to believe that the problem is being caused by a problem with the Library.
> In regards to this issue, could you attach some screenshots to the thread?
I doubt, that a screenshot would be of any help, because the screen went completely blank (except for the first static introduction screen).
> Also, have are you having problems with any other applications?
No, but we haven't tested with any other fullscreen application yet; the problem was first brought to us by our customers. But one of them reported also problems with some older apllication (don't know which)
> If this is happening with various different graphics controllers, we would be more led to believe that the problem is being caused by a problem with the Library.
The problem came into place with the introduction of the second generation Core i processors. We don't have problems with any other graphic controllers so far. Even the Intel desktop graphic controllers work fine.
And why does it work in dual monitor mode at all?!
it's not possible to share our - commercial - program unencrypted, but as we use the Allegro (version 4) environment you can test with some of the delivered example programs.
I put them here:
One thing I forgot: You may also use a demo version of our application, which can be obtained here:
To see the problem start a subtest from the "Test" menu, e.g. "Alertness".
Further in our investigation we are able to reproduce the issue with
http://www.psytest.net/uploads/Downloads/TAP-Demo-en.zip . However tried with we are unable to reproduce issue with the sample programs mentioned in
Would it be possible you to provide a scaled down application with corresponding source code which illustrates the issue?
We have not been seeing this issue with any other applications.
strange, that you could not reproduce it with the Allegro sample programs.
Our programmer just stated, that the problem doesn't exist with Allegro version *5*, but with the older version *4* (which we use).
The corresponding alleg42.dll is included in http://www.psytest.net/download/Allegro.zip.
Or did you use another Allegro library of version 5?!
what is still "funny" about the whole issue: Why does in work in dual monitor mode at all (on both displays)?
As a workaround we provide a "VGA-Dongle" to our customers (a simple VGA connector with some resistors), forcing the driver to switch to dual monitor mode.
Any idea what is so different between single and dual monitor mode leading to this result?
what comes to mind additionally: Could it be some energy saving setting?
The background ist, that we have to set the Intel graphics energy setting to "maximum performance" before on some laptops with Intel chipset graphics to avoid black screens.
As the "maximum performance" setting doesn't help with HD2000/3000 graphics...could it be that some kind of setting ist *always* activ in single monitor, but not in dual monitor mode?