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Replying to and
For the Pixel 2 XL, the issue we had is that the LG battery kernel module was broken when built into the kernel instead of loaded as a dynamic kernel module. I'd guess that you're using an OS build with it built into the kernel and maybe it's missing appropriate workarounds.
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The non-XL Pixel 2 has an HTC battery kernel module. It's possible that it has a similar issue. We had a couple fixes applied for the Pixel 2 XL. The issue that I used to have is that fast charging wouldn't kick in with a generic charger or USB-C to the computer.
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Replying to and
I don't think we had a commit fixing it for the non-XL variant but I remember it being an issue. It's probably a similar issue. In my experience, both in-tree and out-of-tree Linux kernel driver modules are often broken when built into the kernel instead of dynamically loaded.
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It's easier to build them into the kernel than dealing with building modules and putting them in vendor. For GrapheneOS we can't even do that as a workaround for issues like this because we want dynamic kernel modules disabled. Easiest solution is probably dynamically loading it.
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Replying to and
I think your best bet to figure out if this is the issue is disabling the module in your kernel build and disabling the sanity checks for kernel module loading so that the init scripts in vendor can successfully load the stock OS build of the HTC battery module from there.
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It's entirely possible to build it as a dynamic kernel module and include it in vendor, but it's easier to build it into the kernel which is why most aftermarket OS builds take that approach. Stock OS uses dynamic modules to optimize loading time and make kernels more generic.
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I'm not entirely sure if that's the issue, but most of the time these kinds of issues are caused by this class of issue. Since the LG battery module was broken because of this, there's a pretty high chance that it's the problem for this HTC one. Tried to init w/o fw loaded, etc.
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If it's not the original battery, that could also be the issue. The battery is involved in fast charging and has firmware and battery health data on it. I guess it's also possible that the battery's NAND storage or whatever it uses died so it has no health data / provisioning.
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Replying to and
this... requires enough effort that I might just live with partially broken charging. especially given that I still haven't fixed the problem with the USB3 pairs in the connector that makes `adb sideload` very hard to use
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Replying to and
Based on that error message, I'm fairly certain that the battery driver or battery is the issue though. If you look at drivers/power/htc_battery.c, you can see it's involved in negotiating the charging rate. Since there's thermal throttling, etc. batteries are very involved.
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