iBasso DX90 Rockbox 4.0 issue

[Josef K.]

Hello,
I just found out that there is a new version of Rockbox and I wanted to try it on my DX90. I overwrote the original Rockbox installation (the ".rockbox" directory on internal memory) with the new version from Daily development builds page. Almost everything is working seamlessly, except one annoying issue: the player does not recognize whether the device is powered by the adapter or by the battery. In both cases, it behaves as if the adapter is plugged in. The statusbar shows the battery level correctly, but it always shows the power icon, never the battery icon. For this reason, it is not possible to set, for example, different backlight times for battery mode and power mode. Is there any way to solve this issue?

I'm using Rockbox on my DX90 for years. I have installed "official rockbox binary builds" from napych.com:
- firmware-dx90-2.5.1-20160716 dual bootloader (based on newest iBasso firmware V2.5.1)
- Rockbox Version: 46f8e0e-150609 (from the same source). This version doesn't have such issue.

EDIT:
In the meantime, I tested the player in more detail and unfortunately I came across several other problems that are more serious.
- The biggest problem is the crackling sound, which appears especially in tracks with higher frequencies (96, 192 KHz, Flac format). I think this is caused by the expansion of frequencies in the new version of Rockbox: if the frequency is set to 44.1 or 48 kHz, the problem almost disappears. Unfortunately, it does not disappear completely, it only becomes significantly smaller. Again, this does not happen in the older version of Rockbox. Or maybe, to be honest, the problem is so small that it is not noticeable
- There is also a momentary interruption of playback when the player wakes up from the screen off mode.

I also tried the original Mango firmware - none of these problems are manifested here. Even tracks with higher frequencies are played without problems.

After all these findings, I think I will continue to use the original version of Rockbox, which works well for me.

However, thank you in advance for any answers or comments.
JK

[speachy]

Almost everything is working seamlessly, except one annoying issue: the player does not recognize whether the device is powered by the adapter or by the battery. In both cases, it behaves as if the adapter is plugged in. The statusbar shows the battery level correctly, but it always shows the power icon, never the battery icon.

The ibasso-specific code hasn't meaningfully changed in nearly a decade, but as it turns out, it was inadvertently switched to using more generic code to query the charging status.  That's switched back now.

You can try the current dev build (which incorporates this change) from:  https://build.rockbox.org/
or wait for the 20240523 nightly.

I haven't been able to test this (I have a DX50 but haven't figured out how to successfully construct a patched OF image...) so please let us know if this works.

[Josef K.]

Charging status problem solved! Thanks a lot!

Unfortunately sound related problems persists.

EDIT:
In the meantime, I tested the player in more detail and unfortunately I came across several other problems that are more serious.
- The biggest problem is the crackling sound, which appears especially in tracks with higher frequencies (96, 192 KHz, Flac format). I think this is caused by the expansion of frequencies in the new version of Rockbox: if the frequency is set to 44.1 or 48 kHz, the problem almost disappears. Unfortunately, it does not disappear completely, it only becomes significantly smaller. Again, this does not happen in the older version of Rockbox. Or maybe, to be honest, the problem is so small that it is not noticeable
- There is also a momentary interruption of playback when the player wakes up from the screen off mode.

The crackling sound still appears even at 44.1 kHz. Not as pronounced, but persistent. I own two DX90s, so I can easily compare both versions of Rockbox. The original version does not have the crackling sound even at 48 kHz. I managed to find a thread on Head-fi where this problem was addressed:

https://www.head-fi.org/threads/rockbox-for-ibasso-dx90-dual-boot-with-mango-stock-firmware.727669/page-46#post-11406865
Problem description: "Crackling noise. As far as I see it is related to android process scheduler. Headwhacker made many changes to fix this issue, I'm looking through diffs on his code and trying to apply his changes. When I'll be absolutely sure it is fixed, I'll think how to gracefully apply these changes to official sources. It would be a real pain to argue these changes, but at least it will let people build rockbox with extra patches from gerrit, just like last Cholero's build."

https://www.head-fi.org/threads/rockbox-for-ibasso-dx90-dual-boot-with-mango-stock-firmware.727669/page-51#post-11471557
Problem solution: "It looks like after so many test builds and tweaks we did with rockbox source, simply disabling second CPU core (with clean source without any buffers or priority tweaks) solved all problems with sound."

Is it possible that the problem has been solved, but the new Rockbox compilation did not use this solution? And would it be possible to fix this as well?

Thank you so much again.
JK