Author Topic: Annoying dynamic contrast effect  (Read 2651 times)

Kiriririn

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Annoying dynamic contrast effect
« on: June 30, 2018, 11:09:01 am »
There seems to be some sort of dynamic contrast baked into the kernel/display, similar to what Intel GPUs do by default on laptops

See here: https://www.youtube.com/watch?v=cys7tbrVlNw (it's not the camera)

It's particularly noticeable in the shade of black/grey on the LXQT menu button and clock when focusing and unfocusing a terminal window

Unless I'm mistaken this is Miravision, which seems to live in /drivers/misc/mediatek/video/common/color20, but I've had no luck disabling it via the obvious config flags (CONFIG_MTK_PQ_COLOR_MODE etc)

Has anyone else noticed this/tried to disable it?
« Last Edit: July 08, 2018, 08:16:11 am by Kiriririn »

Kiriririn

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Annoying dynamic contrast effect
« Reply #1 on: July 07, 2018, 01:45:30 pm »
Solved!

Simply set this in the kernel config:

Code: [Select]
CONFIG_MTK_AAL_SUPPORT=n
Nice increase in image quality with this change (things look closer to how they should), god only knows what mediatek were thinking with this
« Last Edit: July 07, 2018, 01:49:47 pm by Kiriririn »

Kiriririn

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Annoying dynamic contrast effect
« Reply #2 on: July 08, 2018, 07:42:39 am »
So it turns out disabling AAL breaks sleep (i.e. screen does not wake up when opening lid, everything else does)

Fortunately there is a simple fix - instead of disabling it in the kernel, add a cron to pause aal - it seems this usermode binary does all the heavy lifting. It autorestarts if killed, so pausing is the only option

Code: [Select]
killall -STOP /vendor/bin/aal

Kiriririn

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Annoying dynamic contrast effect
« Reply #3 on: July 10, 2018, 01:15:19 pm »
Hacked the above fix into repowerd to allow brightness control to still work, anyone interested can find it in this commit: https://github.com/lukefor/repowerd/commit/...c4b82487db3e750