Linux Frame buffer Display Startup Problem

[madhu]

Hi,

I have some different problem with display.

When ever I'm running my application it is not showing properly. If I kill the application and run again its working fine.

You can find the difference between two images in the attachment.

 

[inmarket]

This sounds like a video mode setting problem.

1. Make sure you are running the latest repo as there were recently updates for the linux framebuffer board file.

2. Have a look in the linux framebuffer board file as there are some optional settings that control the initialization sequence as different linux kernels exhibit slightly different behaviour.

 

[Joel Bodenmann]

Information that might be valuable to track down the problem:

• Does this happen every time you start the program (eg. do you always need to launch it twice)?
• Does this only happen once after you rebooted and then never again?
• Do you see any debug message on the terminal?
• What happens if you call the driver initialization code a second time manually (within the same program)?
• Anything else that would help to establish a pattern...

[madhu]

Hi,

This happens only once after reboot and never again. I did not find any debug message on the terminal.

[Joel Bodenmann]

The distorted image you see on the first startup, is that always exactly the same?

[madhu]

No it depends on demo what we are running.For example if I run button demo it looks different and if i run widget demo it looks different.

Note:And also my board got splash screen when I turn on the board it I'll come and it I'll remain until run any framebuffer demo

is it making any problem...?

Edited September 13, 2016 by madhu

[Joel Bodenmann]

As mentioned in a previous post this definitely seems to be a video mode initialization issue. Stepping through the code might be the most reasonable way to track down & fix this problem.

Also, please try, as mentioned, what happens when you call the driver initialization code twice. It would be good to know if this only happens once per startup of the driver or the entire process.

[madhu]

It is working fine when I'm calling driver initialisation code twice.

[Joel Bodenmann]

I'm not really sure where to go with this...
As mentioned this definitely seems to be an issue with the video mode settings. However, the driver would call exit() to stop the execution of the program and print an error message to stderr if any of the initialization code failed.

Did you try playing around with the defines in the board file as @inmarket mentioned in his first post?

#define USE_SET_MODE				 // Optional - comment this out to not to try to set the color mode we want
//#define VTDEV_PATH	"/dev/tty0"	 // Optional - if defined use this tty to switch from text to graphics mode