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Old 12-07-2018, 04:11 AM   #1
Dominique U
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Changing minimum brightness on PW4

I have a PW4 (jailbroken), and there are two things I am unhappy about with the new frontlight settings:

* When setting the frontlight to minimum, it is 100% off. (I know that many people actually want that, but I found it problematic when I accidentally switch off the frontlight in the dark and then cannot see the buttons to switch it on again.)

* When setting the frontlight to the next higher setting, it is already too bright. (I used to read in the dark with the lowest setting on PW3, and the lowest non-off setting on PW4 is much brighter than that.)

So, my question is: How can I change the brightness levels offered by the PW4? Ideally, I would like to just edit the mapping from UI-levels to actual brightness, but if that's not possible, I would settle for a solution using, e.g., a cron-job that sets the brightness to the right level.
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Old 12-07-2018, 05:45 AM   #2
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https://www.mobileread.com/forums/sh...d.php?t=288547
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Old 12-07-2018, 01:48 PM   #3
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Note that on the PW4, the sysfs path should be /sys/class/backlight/bl/brightness instead .
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Old 12-08-2018, 11:25 AM   #4
Dominique U
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Quote:
Originally Posted by hius07 View Post
Thanks. Unfortunately, that does not seem to work on PW4 for making the frontlight less bright.

Code:
cat /sys/class/backlight/bl/brightness
(which seems to be the frontlight device on PW4, the path has changed) gives 20 on minimum brightness (level 1 in the UI), and gives 0 when the frontlight is off (level 0 in the UI).

So I assumes that
Code:
echo 1 > /sys/class/backlight/bl/brightness
would give me a very low brightness. Unfortunately, that is not the case. Putting 1 here gives the same brightness as 20. (But the file works, putting 0 switches the backlight off, putting 1 switches it on again.)

So, by just writing numbers into this file, it seems that I cannot switch the frontlight to a low intensity (comparable to PW3).

Does anyone have an idea what else I could try? The bright light is a strong disappointment for me, I am missing my PW3.
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Old 11-29-2020, 12:35 PM   #5
j.p.s
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What are the files in /sys/class/backlight/
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Old 11-29-2020, 03:48 PM   #6
Dominique U
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Quote:
Originally Posted by j.p.s View Post
What are the files in /sys/class/backlight/
I can't tell. I lost my PW4 last year (after it unjailbroke itself anyway), and switched back to a PW3 because the backlight is less bright. Still hoping for a new model with a less bright backlight before my PW3 finally gives up the ghost.
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