linux refresh screen

[Carpe Diem]

With labview for linux 6.1,(in every application) each time I pass from one panel to the next one I see a white screen preceding the correct one. This create an unpleasant flashing and delay in the user interface of my application.
Is it possible to avoid it?

[Jeremy Braden]

I do not use LabVIEW for Linux, but what I suspect the behavior you are seeing is due to your video card. You might see if there is an update for your card or try another card for troubleshooting purposes.

[Carpe Diem]

Thank you Jeremy for your answer, but I don't think so because I note this effect both in two different desktops and a notebook pcs.
Does anybody tried to make a simple application with labview linux and note it? Apparently it comes only from a lv application.
PS: the slower is the processor and the more is evident, of course.

[Kevin Valentine]

Are you using NI Visa? That can have an affect on the whole OS if you don't know to hide the visa controller... more on that if you need it. I don't fully understand what is happening in your situation. When you say panel are you talking about the front panel of a sub-vi? Does it happen only when the application is running?

Please send a very basic example that would be representative of what you're seeing. I must emphasize the need for a BASIC example. We want to rule out any problems due to unruly subVIs. Also, please save it as 6.0 (that's what I have). I know this may make my verification null and void but at least then you'll know it's possibly a 6.1 thing. What video card are you using? What version of xfree86? Mine is 4.1.0 and I have never seen
this flickering in LV 6.0. Have you previously run LV 6.0 and seen similar behavior?

-Kevin

[waldemar.hersacher]

I don't know how you get from one screen to the next. I suppose you do the following:
From a VI you call a sub VI with the attributes "Show front panel when called" and "Close afterwards ..." set. If you call sub VI 1 its front panel is opened and if you are leaving it the front panel is closed. Then the caller will call sub VI 2. This will cause the flashing on the screen.
I have done the following solution:
On the connector pane I have a reference to a VI. The VI which front panel is to display will do the steps:
Set up all indicators and controls
Show the front panel with the attribute FP.Open
Wait a short time to let the video subsystem do its work
Close the front panel of the VI with the reference of the connector pane with the attribute FP.Open
and close the reference. If you are not sure that you will always get a valid reference check it first.
On exit give the reference of the VI over the connector pane to the caller. He can give it to the next VI.

Waldemar

[Kevin Valentine]

I don't get this flickering in 6i. I just double checked by making a simple app that would call a subvi. No flickering. Is this a known problem in 6.1? I've run LV6i for linux on 90, 233, and 933MHz machines but I've never seen this flickering you speak of. Are you saying that video adapters under linux have a difficult time keeping up with LV's panel refresh rate? Perhaps you need to do some tuning in your XF86config. A lot of distros default to using the frame buffer driver (fbdev) in the config file. I've had mixed results in quality from this setup.

I think dynamic loading is a good idea for calling most VIs. I guess if it's your only solution then go with it.

- Kevin