Lcd Problem

[sbseb88]

Hi,

I have had my GP2x for quite some time now. Recently (I think a couple months back) I spotted a problem with my LCD screen. It showed 2 to 6 pixels in the lower-right bottom of the screen in the wrong color. Let me explain via a picture:

The pixels seem to be copied from the left side of the screen. The pixels are not stuck - they're just not the right color.

I've tried updating, the problem persisted on firmwares 2.0.0, 2.1.0 and 2.1.1. However, on fw 2.0.0, when I adjusted the LCD slider to the right, the problem would disappear. On fw 2.1.1, when using gpFCE v0.3 in fullscreen mode, the problem also seems to be gone.

I'm going completely bonkers on this. Does anyone have any idea what could be causing this, and possibly a fix?

 

[ruckage]

I have noticed this on mine and i think it must be a software/firmware problem as it doesn't occur in every program. To be honest though as it doesn't happen on every program and it's confined to the last few pixel on the last row of the lcd it doesn't really bother me. If they were in the middle of the screen I would be more bothered.

The only thing I can think of is that its to do with the screen refresh though it's only a guess.

 

[sbseb88]

I have noticed this on mine and i think it must be a software/firmware problem as it doesn't occur in every program. To be honest though as it doesn't happen on every program and it's confined to the last few pixel on the last row of the lcd it doesn't really bother me. If they were in the middle of the screen I would be more bothered.

The only thing I can think of is that its to do with the screen refresh though it's only a guess.

It didn't bother me before, but now that I've spotted it... I did some test with CPU/LCD tweaker
Display: UPLL, timing = 1. Then, in gpFCE, running at 200 Mhz (or more), the problem was there; 150 through 166 Mhz the problem vanished; below 150 Mhz the problem came back. You're probably right about the screen refresh.

Anyway, thanks for replying so fast. It's also "nice" to know I'm not the only one with this problem...

 

[Mudi]

It's a bug in certain versions of hardware SDL as far as I can tell.

 

[Alex.]

The bug is always happening. It even occurs in the firmware's photo viewer. The programs that appear not to be affected by it simply happen to have the same colours in the spot that they're picked from as the colours that should be in the bottom-right corner.

 

[A_SN]

It's a bug in certain versions of hardware SDL as far as I can tell.

Nope. I write to the framebuffer and I get that too. And the way you know how it's not a software problem (I guess) is that even when you stop writing anything to the screen it keeps on jittering. lcd's controller problem I guess.