Linux logo ---> EwGUI main & double buffer

Question

Hi   

We use following software components.  

- Embedded Wizard Studio Pro v9.10 

- Embedded Wizard Platform Package for Generic RGBA8888 

- Embedded Wizard Build Environment for Generic RGBA8888 

- Generic RGBA8888 NEON AddOn  

Our target system specification.  

- NXP i.mx6 quad and Yocto embedded linux.

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The ew gui application will launch automatocally when the linux boot is complete.

My Linux boot logo and appear normally.

However, after the Linux boot is complete, the screen below appears before the main screen of the my GUI application appears.

The reason why the unexpected screen appeared was because of a double buffer. (compile with EW_USE_DOUBLE_BUF)

In the EwBspDisplayInit function, the screen changes as soon as the code below is performed.

        ioctl( FbDev, FBIOPUT_VSCREENINFO, &VarInfo );

If a double buffer is not used (compile without EW_USE_DOUBLE_BUF), the following screen will not appear.

But I want to use a double buffer and move directly from the Linux logo to my GUI main.

What should I do?

 

Best regards

 

 

 

 

 

Answer 1

Hello,

it seems that the ioctl() changes the memory area of the framebuffer and shows an uninitialized memory content.

Can you switch to double buffering already during the start of the system, so that there is no reallocation necessary?

Otherwise - just as a workaround - you can turn off/on the backlight?

From user-level (as EwBspDisplayInit() is running) I do not see a chance to initalize the memory before the ioctl() call.

Best regards,

Manfred.