topic Re: Flicker and black screen clear while starting Xorg in i.MX Processors

Flicker and black screen clear while starting Xorg

vikaspatil — Wed, 08 Apr 2015 10:23:26 GMT

Hi All,

I am working on to implement the splash screen on i.MX6 solo based custom platform using Linux 3.10.17. I am able to display custom splash screen using u-boot and linux framebuffer console(i.e. fbcon, linux logo).

I have also written one frame-buffer application where it writes splash image to /dev/fb1 and enabled global alpha and set it to 0x00 for /dev/fb0 to make

/dev/fb1 (splash) visible just before the xorg starts and just after starting the UserInterface, another application again sets global alpha of /dev/fb0 to 0xFF and after that disables the global alpha for /dev/fb0 to make /dev/fb0 (UserInterface) to visible.

My understanding was if I use /dev/fb1 to display splash image and as Xorg uses /dev/fb0, splash image would remain intact/untouched while xorg starts.

So in this sequence I am observing flicker and screen clear with black by Xorg. I have tried modifying xorg-server-1.14.4 and xserver-xorg-video-imx-viv-3.10.17-1.0.0 in various ways but it didn't help.

How could I avoid this flicker and black screen clear while xorg starts?

Do you have any suggestions/ideas to avoid/remove this flicker and clear?

Regards,

Vikash

Re: Flicker and black screen clear while starting Xorg

igorpadykov — Thu, 09 Apr 2015 10:43:51 GMT

Hi vikash

flicker occurs since linux uses different than uboot IPU settings, so

ideally you should configure IPU in uboot and do not touch it in linux.

Possible solution may be to be fast enough in the bootloader and show

a splash screen under Linux only.

Best regards

igor

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Re: Flicker and black screen clear while starting Xorg

vikaspatil — Thu, 09 Apr 2015 11:56:48 GMT

Hi Igor,

Thanks for reply. Yes, you are right. Need to configure ipu in u-boot and avoid changing it afterwards however that requires lot of work as you mentioned on some other post. I found the patch to do it but it is for older kernel. see below the threads.

https://community.freescale.com/message/472960#472960

https://community.freescale.com/docs/DOC-98109

Using "“-sharevts" to xorg command line fixes the flicker which we observed while xorg starts.

Regards,

Vikash