Screen flickering only with X11 Desktop manager

[mushketer888]

Strange but LCD screen is flickering only with X11 and some dekstop manager
For example x-screensaver doesnt flicker at all!
And terminal also (ctrl-f1 etc)
What can be the cause?

[mushketer888]

Very strange
I edited fex to

lcd_io_cfg0 = 268435456

and all worked well

[martinayotte]

Effectively !
I've recently upgraded to A20-Debian-release8 (I was using rel4), and I had to tweak lcd_io_cfg0 again.
I don't know why this old issue isn't fixed forever in newer releases.

[rouvas]

Where was that value you edited? In some config file?

[JohnS]

Each of you - which LCD are you using?

John

[rouvas]

I am using A13-LCD10TS. To be honest, I haven't observed any flickering, but then I'm not loading LXDE either. I stop at openbox.

[martinayotte]

I'm using both LCD10TS and LCD7TS and I was facing the this flickering issue since the beginning until last June, when I discovered a thread where someone find a fix using lcd_io_cfg0 = 268435456 in FEX file, I've apply this fix and since then, I don't have the issue anymore.
The flickering was intermittent depending of the contrast of the background images used in my application.
I think this fix should be permanent in /root/change_display_a20_olimex.sh but it isn't there yet.

[dave-at-axon]

That value is hex 0x10000000 and sets bit 28 of the TCON0_IO_POL_REG to 1 and I mentioned this here before:

https://www.olimex.com/forum/index.php?topic=2933.msg13211#msg13211

Still not found out what it changes as limited documentation.

[JohnS]

Thanks, everyone.

If it's changing a phase then a 'scope, data sheets and some work ought to reveal it.

Or just set it and when it works move on

John (who doesn't even own the LCD or have the skills to use the 'scope if I did!)

[dave-at-axon]

I'd like to check what is does so I plan to hook up a logic analyser when I get a little time to play with it and then try the different settings.

I just tried out a Newhaven 7" LCD today and although it did display without any timing changes, there is a little bit of an issue that I think can be sorted though timing changes.