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There are reports of screen tearing in more erecently released Dingoos, the black ones in particular. Are many other Dingoo owners experiencing this?

I have noticed that not all games show screen tearing, and TV out works fine, no tearing at all.

Whats causes screen tearing? Is it the refresh rate of the display? Could it be a firmware issue or faulty drivers of some kind?

If it is the refresh rate of the display, can a limit to the refresh rate be set in software?

Is the tearing diagonal or horizontal?

There is diagonal tearing on the screen in some games, usually those that scroll very quickly. In Fronty Mission Gunhazard with the english translation patch applied to the rom, there is a little horizontal tearing on the right hand side of the screen and a vertical line of tearing on the right as well, but it may just be a glitch in the snes emulator as it is only in the intro, not in gameplay.

But the worst is the diagonal tearing when it is visible. Gunstar Heroes for example looks terrible because of this, but works perfectly on tv out.

Some nes games get the diagonal tear when transitioning between screens, like a fade in/out at the start or end of a level in gunsmoke for example.

Chances are the diagonal tearing is always happening, it's just more noticeable under certain circumstances.

Thanks for replying Exophase. Just out of curiosity, is there a potential solution to the problem that could be implemented in the future? And generally, what would be the reason for the tearing? Firmware bug or hardware issues?

Check out the post I mead in the Wiz forum. Based on the document I've seen for the (a?) LCD controller for the Dingoo it's probably the same issue.

Will do. Thanks.

Is the tearing on the megadrive/genesis emu?

If so it's a bug in the emu itself.

Just a note, there are (AFAIK unfounded) theories that some dingoos have different LCD controller. You can verify it on your device by hidden info described here http://a320.bluwiki.com/go/Eastereggs
There is one line that clearly states type of LCD controller, mine is Ilitek ILI9325 for sure.

It looks like it can be reconfigured to update screen in its native format (240x320 not 320x240) to eliminate diagonal tearing but then you need to rotate it via CPU before sending to display which is costly. Or maybe some emulators could generate rotated screen output directly or could be modified to do so to avoid/minimize this penalty?

If the LCD controller is different then either it needs to provide multiple buffers or it needs to be 320x240 along with the display. Emulators can be modified to send rotated data but sometimes it's trickier than it seems.

@craigix: It happens in cps1, nes and snes as well depending on the game. Some games seem to be fine, others have the diagonal tearing and some snes games seem to have vertical tears at the edge of the screen, but that could be a bug in the emulator I suppose.

@fanoush: My LCD Module is ILI9325. Does your Dingoo get the tearing?

I'll grab a black unit and take a look, I'll try to do a video if possible.

Yes, I see the tearing. Most probably everybody has ILI9325 in A320. The firmware recovery tool provided by Dingoo has only one flashing driver loaded into device over usb and that driver has ILI9325 in its name.

If the controller/LCD is the same then the only other explanation is a change in software where either the output is being rotated/rendered in a rotated fashion or there's some support hardware that's performing it. Since they control most of the software right now it's not impossible.