09-13-2023, 04:46 AM | #1 |
Member
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Device: Nook Glowlight 4e
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Deep sleep in glowlight 4/4e and modern nooks
Hi,
jumping from NST to "glowlight 4" (4e actually) I was disappointed at how little a single charge were allowing to read. Direct tests revealed something like 8 hours of reading from 90% to 10%. This was mostly with third-party readers. Then, I installed BetterBatteryStats (BBS) and made some observations, hoping that as I expected, the system would fall into Deep Sleep from time to time outside of the locked state. It was to no avail except when I noticed that the BN reader app did fall into DS between page turns. Since then I never noticed any other app to activate DS. Actually the deep sleep behavior of BN app was also non-constant. The primary observation is when I made different tests when the delay between turns were different and I calculated the time spent in the full wake state, there was a constant wake time about 6-10 seconds that could never be decreased. But for 30 seconds page turns it was already ok for saving the battery life. I have plans to investigate whether an app can force the system to fall into DS without going into the lock mode or changing the screen contents, but I would like to be sure the things I noticed are the same for all devices in the wild and it's not specific to my particular instance. If somebody from the community may find time and take some tests, that would be very useful. I will explain how I did mine, but I'm sure there are other apps and other means to achieve the same. So, the questions are:
So my testing steps :
Any results are appreciated. Thanks. |
09-13-2023, 01:22 PM | #2 |
cosiñeiro
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Device: BQ Cervantes 4
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Most likely yes. The Nook reader app at least. Probably the other stock apps if there's any.
It also might be possible to do it on 3rd party apps but it is not part of android, so it requires a developer with a device that does RE the binaries to know which function call trips the DS. There's a chance that the specific code path is restricted to system apps, so nobody can tell you without doing the work first. Good question. I bet the old ones where you didn't had the chance to run 3rd party apps were not affected, but I'm not really sure. My answer is based on 1. They were Freescale/iMX boards with a good idle power draw 2. Running very old versions of android where Doze isn't available. |
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09-14-2023, 05:58 PM | #3 | |
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Quote:
Also it just happened that I rooted my 4e and grab the logcat after a dozen of page flips in the BN app (bn.ereader). Looks like they use some proprietary lib epdUtils (probably vaguely googlable in the context of Sony eInk readers, epd probably stands for Electronic Paper Display) and the method (or call) setDirectSuspend. When the line with true ....EpdUtils: setDirectSuspend: true then 2.5 seconds pass until the system goes to deep sleep and the logcat stops reporting anything at all until (in my case) hardware button KEYCODE_F11 is pressed, after that about 3.5 seconds passes until the corresponding call is noticed ... EpdUtils: setDirectSuspend: false The 6-7 unavoidable seconds I previosly mentioned is this 2.5 + 3.5 seconds between these calls. Now I really doubt anyone can find a non-B&N app performing the same wizardly... |
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09-22-2023, 06:14 AM | #4 | |
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Quote:
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