[Android Software/Hacking General [Developers Only]] LorDestinY:
Backlight flickering

Originally posted here >>> [ROM] Vodafone 845 Mr. Edition

It concerns kallt_kaffe since his kernel is used on freddyemmer Roms.

>> Issue:

When back light is set to minimum the back light flickers.

>> ROMs tested:

Vodafone 845 Stock ROM

Mr Edition v2.0.1 "original"

Mr Edition v2.0.1 + kallt_kaffe OC 729.6 Mhz

Mr Edition v2.0.1 + kallt_kaffe OC 710.4 Mhz

Mr Edition v2.0.1 + kallt_kaffe OC 691.2 Mhz

Mr Edition v2.0.1 + kallt_kaffe OC 672 Mhz

Mr Edition v2.0.1 + kallt_kaffe OC 652.8 Mhz

Mr Edition v2.0.1 + kallt_kaffe OC 633.6 Mhz

>> ROMs to be tested:

Mr Edition older versions

wildgunman - V8 Rom v1.7.6

kallt_kaffe - The Celestial Teapot RLS3

>> Results:

1º - Mr Edition v2.0.1 + kallt_kaffe OC 729.6 MHz = Stable, backlight flickering

2º - Mr Edition v2.0.1 + kallt_kaffe OC 710.4 MHz = Stable, backlight flickering

3º - Mr Edition v2.0.1 + kallt_kaffe OC 691.2 MHz = Stable, backlight flickering

4º - Mr Edition v2.0.1 + kallt_kaffe OC 672 MHz = Stable, backlight flickering

5º - Mr Edition v2.0.1 + kallt_kaffe OC 652.8 MHz = Stable, backlight flickering

6º - Mr Edition v2.0.1 + kallt_kaffe OC 633.6 MHz = Stable, backlight flickering

7º - Mr Edition v2.0.1 "original" = Stable, backlight flickering

8º - Vodafone 845 Stock ROM = OK

>> How issue happens:

If backlight is set to the minimum value "1" after some moments in sleep mode it starts to flicker when you turn it on again. If its set to next level "2" it works normally. Usually it only happens after i put phone in sleep mode "press power button" and usually doesn't happen instantly. Some times the flickering is very light but rarely. (Tested using the Settings menu slider for better results)

>> How to identify issue:

I identified a method of knowing if the bug is happening even if its not flickering.

If you press power button to put phone in sleep mode while backlight in minimum value you will notice that before the screen shut down the backlight will slightly light up and then turn off.

In Stock ROM it just smoothly turns off.

1º - Set backlight to minimum value.

2º - Press power button to put phone in sleep mode.

--> Notice that the backlight will slightly light up before turning off screen.

3º - Wait some seconds. (+60 seconds for optimal result)

4º - Press power button to wake phone from sleep mode.

--> Noticeable flickering.

I originally thought that i damaged the phone with the 729.6 MHz overclocking.

I done a lot of stress tests and benchmark before i decided to keep it overclocked. It was stable, no errors and no random hangs/restarts/shutdowns. Next day all good besides the flickering. I ussually don't use backlight at minimum value, so i didn't noticed if after installing the Mr Edition ROM v2.0.1 for the 1st time it was already there, or if it was +-9 hours of 729.6 MHz overclocking that damaged the phone.

I don't think this is hardware related or else the issue would also happen with stock ROM. Well i'm not an electronic engineer, but i don't think that CPU frequencies is related with LCD backlight power control.

Going to test with older versions of Mr. Edition ROM. I'll keep you informed.

If someone else is having this issue and/or fixed it please tell me.

Peace...

***** UPDATED 20/11/2010 - 22:00

Tested with ROM: kallt_kaffe - The Celestial Teapot RLS3 >>> BAD - FLICKERING

Tested with ROM: Vodafone 845 Mr. Edition v1.6.2 >>> LauncherPro Expired, GOOD - NO FLICKERING

Tested with ROM: Vodafone 845 Mr. Edition v1.8 >>> GOOD - NO FLICKERING

Tested with ROM: Vodafone 845 Mr. Edition v1.9.1 >>> GOOD - NO FLICKERING

Tested with ROM: Vodafone 845 Mr. Edition v1.9.5 >>> BAD - FLICKERING

Tested with ROM: Vodafone 845 Mr. Edition v2.0.1 >>> BAD - FLICKERING

Not tested: wildgunman - V8 Rom v1.7.6 >>>

UNSIGNED

Rom. Need ClockWork Recovery to install it.

I still haven't tryed all the ROMs from kallt_kaffe but from what i already tested i came to the conclusion that the flickering problem is related with the usage of kallt_kaffe kernel. The backlight flickering started to happen on Mr. Edition v1.9.5 with the newly added Kallt_kaffe OC_633 version kernel.

For now i'm going to stick with stock ROM :(. I'm afraid that this weird backlight power surge damage my phone.

Going to put this same post in [ROM] [Huawei U8100/U8110/U8120] [Eclair] The Celestial Teapot RLS3 thread and hope that freddyemmer and/or kallt_kaffe fix it so i can use this awesome ROM.

Thanks you.