OESF Portables Forum
Model Specific Forums => Gemini PDA => Gemini PDA - Linux => Topic started by: Kiriririn on June 30, 2018, 11:09:01 am
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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 (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 (https://www.mediatek.com/blog/what-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?
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Solved!
Simply set this in the kernel config:
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
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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
killall -STOP /vendor/bin/aal
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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 (https://github.com/lukefor/repowerd/commit/88ec9140dd4063728182378a2c4b82487db3e750)