[KERNEL][3.18.140+][EOL for now] SwanKernel for the LG V20

[itt533]

Yea my bad i meant unprocessed, Also are you editing mixer_paths_tasha-quad_dac or mixer_paths_tasha? And do you keep the dac enabled?

only mixer_paths_tasha and dac is disabled during my tests.

 

[itt533]

IR Blaster is pretty much identical to Lineage's built-in kernel, mk2000, and anything newer than the oreo builds of the gamma kernel, which means it doesn't work for now. But if you want to test it, "Lean Remote" is what i use to check if it is sending IR signals.
[ ... ]

i tried the ir blaster with an ir detector, which doesn't see the data carried. The first time it triggers one shot. My lg tv did not react at all. After that shot, it continues emitting an alternating signal of about 1~2s period. There is no way to stop it, despite killing the ir app, and worse... even once the phone is turned off it continues emitting for 2~3s and stops.

 

[AShiningRay]

i tried the ir blaster with an ir detector, which doesn't see the data carried. The first time it triggers one shot. My lg tv did not react at all. After that shot, it continues emitting an alternating signal of about 1~2s period. There is no way to stop it, despite killing the ir app, and worse... even once the phone is turned off it continues emitting for 2~3s and stops.

That's the current behavior alright. The first command works (assuming your TV, AC, etc responds, my LG TV does at least), but then the phone's IR blaster stays unresponsive due to that intermittent flashing for quite a while before another command can be issued. We logged it pretty extensively a few months ago but came to no concrete conclusion as of yet, although it seems to be related to the kernel's tty ports.

 

[itt533]

That's the current behavior alright. The first command works (assuming your TV, AC, etc responds, my LG TV does at least), but then the phone's IR blaster stays unresponsive due to that intermittent flashing for quite a while before another command can be issued. We logged it pretty extensively a few months ago but came to no concrete conclusion as of yet, although it seems to be related to the kernel's tty ports.

kernel's tty ports? is it assumed that it's a problem with the driver?

 

[AShiningRay]

kernel's tty ports? is it assumed that it's a problem with the driver?

Nope, not the driver exactly. I compared the irrc's files with gamma's oreo branch and those are identical on lineage, mk2000, swan, etc. It seems to be somewhere on the bridge that connects those drivers to the userspace (i.e. The OS and apps requesting actions from the IR), where exactly, we don't know yet. It's one of the things we're also looking at in the 4.4 kernel in hopes of fixing it there.

 

[itt533]

Nope, not the driver exactly. I compared the irrc's files with gamma's oreo branch and those are identical on lineage, mk2000, swan, etc. It seems to be somewhere on the bridge that connects those drivers to the userspace (i.e. The OS and apps requesting actions from the IR), where exactly, we don't know yet. It's one of the things we're also looking at in the 4.4 kernel in hopes of fixing it there.

then, did you investigate the stock ir remote app?

 

[xxseva44]

then, did you investigate the stock ir remote app?

Stock ir app will not work on custom due to it's reliance on the lg framework. Besides ir is confirmed to work on gamma with 3rd party apps, so there isn't much to be gained from looking at lg's app.

 

[xxseva44]

only mixer_paths_tasha and dac is disabled during my tests.

Hmm weird, yea not sure, it should be working.

 

[stingbandel]

Can I use swan on oreo stock?

 

[aCIDsLAM]

Using swan kernel makes the device snappier but i get random reboots on h918.
Not sure it ifs sdcard access related. I may test a bit more.

 

[abdoistheone]

IS THIS KERNEL COMPATIBLE WITH LG G5 H830 & WHAT ANDROID VERSION IS SUPPORTED ?

 

[TappedCeiling46]

View attachment 5441323

A custom kernel for (most) V20 variants​

SwanKernel is an android kernel based on the latest Lineage OS 18.1 sources for the LG MSM8996 phones, aiming to bring those features and updates and improve them with some extra tuning, fixing and external features tailored specifically for the LG V20's performance characteristics and feature set, while trying to maximize the battery life and responsiveness of the device at the same time.​

This kernel is based on Linux 3.18.140, and has become EOL with the last commit, as i don't think there's anything else that can be optimized for the V20 on this source anymore.

​

Which phone variants/models does this kernel support?​

The kernel currently supports the following variants:

• H910/H915
• H918
• H990
• LS997
• US996
• VS995

Support for other special variants like the US996Santa might come at a later date if needed.

What does this kernel intend to achieve?​

The main goal here is to have a kernel that not only has extra features and improvements, but is also clean and concise, having only features that are truly needed from a kernel that will run alongside a Android 11-based ROM. One example of that is Kcal display control, a feature that is unnecessary here since most, if not all Android 11 ROMs have LiveDisplay for that exact same purpose and without the need to root. This helps the kernel have a smaller file size and lower processing overhead, as well as promote better maintainability.

This kernel does have a battery life bias, but will still scale up to maximum performance when needed. No Overclocking is done for now.

Does it have any features over stock?​

Yes, a lot. The kernel is divided into two variants, here are the features both variants have over stock:

1. AdrenoBoost for improved GPU performance.
2. GPU and CPU/Cache Undervolt for better power efficiency on load.
3. CPU governors tuned for better battery life and thermal stability without impacting performance all that much.
4. Almost no unnecessary debug flags on the kernel for better kernel performance.
5. Westwood TCP Congestion Algorithm set as default in order to have better network performance and consistency.
6. AutoSMP CPU Hotplug to shutdown the big cores when their stronger performance isn't needed, slightly improving battery life on light loads and idle.
7. Disabled CPU Boost when a finger is detected on screen, preventing unnecessary frequency boosts when no meaningful action is done other than tapping on screen and slightly scrolling around. We have Schedutil to keep it smooth anyways.
8. USB Fast Charge.
9. Multiple cherry-picks from different msm8996 sources with fixes and improvements to the kernel.
10. Configurable wakelock blocker (boeffla) for roms that have some "unneeded" wakelocks enabled by default and/or users that know which wakelocks can be blocked for better battery life.
11. Anxiety IO Scheduler enabled by default, offering a read bias and lower latency in IO operations.
12. Kernel updated to Linux 3.18.140 with some extra patches from Googlesource.
13. Wireguard support, improving VPN performance.
14. Cryptographic functions optimizations, slightly improving the phone's performance when calculating hashes and so on.

The Extreme variant has some extra features over the Stable one, those being:

1. Stronger Undervolts (i'm talking about borderline unstable undervolts here, so i really recommend that you flash the Stable one first).
2. CPU Voltage Control if you need to setup a custom undervolt to keep it more stable and have no need to compile the kernel from source just to change the values... and that's assuming your phone even boots with this variant of the kernel.
3. Disabled Battery BCL which eliminates the power throttling caused by the battery, just be careful when running demanding tasks while having almost no battery left.

Are there any bugs?​

Right now, there's the dreaded Infrared Blaster, and it... kinda works? The IR is able to send the very first command i give to my LG TV without any problems after every reboot, but refuses to send anything else after that first command. The IR Blaster's light still works all the time though despite having some big delays between on/off states.

Download & Installation​

The folders containing each kernel variant can be found here:

• Stable Version
• Extreme Version

To install the kernel, it's the standard procedure:

1. Download the kernel you want for your device
2. Place it into the phone
3. Boot into recovery, select it and then flash
4. Wipe Dalvik Cache (optional, you only need to wipe it if you face random Force Closes, but it is a good practice anyway)
5. Reboot.
6. Open any app that can check the device info and look for "kernel", where it will show "... 3.18.xxx-Swan" if it installed correctly. I personally use SmartPack for that, but it requires root.
7. Enjoy the experience!

Performance and Battery metrics​

Spoiler: outdated (done in v1.00), performance has improved since then:

And now to the kernel's real world performance. But before delving in, keep in mind that my refurbished H910 is apparently a Snapdragon 821 prototype, that's why you will see higher than normal performance and clock values on cpu matters even with the LITTLE cores underclocked to 1785MHz instead of 2188MHz, the snapdragon 820 ones should not have any underclock applied and will reach the max of 1593MHz on them. I also took the liberty of testing those on the Extreme variant as BCL often interferes with the performance results and the extra undervolt doesn't increase performance in any substantial way, 5-7% at most on Geekbench.

Battery life:
Screen SOT test (Youtube looping through a massive playlist of songs with some scrolling to change between them):
View attachment 5441455View attachment 5441457

Not very impressive, until you consider the battery currently powering it:
View attachment 5441459

CPU/GPU Performance:

CPU performance according to Geekbench 5.4.1 (there is some minor variance of about 15-21 points in multithread):
View attachment 5441461

CPU sustained performance on CPU Throttling Test(running it for 15+ minutes barely changes the curve, as it stabilizes at around 80-82 Celsius, i suppose a Snap 820 will fare better here due to the lower clocks):
View attachment 5441463

GPU general performance on GFXBench 5:
View attachment 5441469

No copper shim replacement or thermal pad change was made, the phone's internal structure is still the same from when i bought it.

Storage Performance:

General IO performance in Androbench 5(Not very accurate, but welp, if anyone has a more in-depth one feel free to share):
View attachment 5441471

And there we go, everything i could benchmark so far. This will not be the best kernel on every front so the stock kernel on Lineage 18.1, Lighthouse's kernel or mk2000 might suit you better depending on your needs.

Changelog​

Spoiler: Changes done in recent versions:

*********** Swankernel V1.09+ [Maintenance release] ***********​

1. CPU/Cache/GPU Voltages have basically reached the optimum point on both stable and extreme.
2. Some performance commits were cherry-picked from newer kernels for other devices
3. Dynamic FSync was disabled since it could cause data loss on some edge cases involving reboots.
4. Improved some string routines and memory access functions, about 4% or so improvement on geekbench.

*********** Swankernel V1.09 [Last 3.18 version, i think] ***********​

1. Minor performance and power-saving optimizations throughout the kernel
2. CPU M4M cache undervolting (not really a big difference, but nice to have anyway).
3. A few cherry-picked fixes for the 3.18 msm8996 kernel tree.
4. Crypto function optimizations and HW acceleration for CRC32 Enabled.
5. Not actually a kernel change but: Can now be flashed on android versions lower than 11.

*********** Swankernel V1.08 ***********​

1. Small performance optimizations related to the voltage curves, especially in the GPU.
2. PC USB Charging has been fixed and the phone can now be charged over it again.

*********** Swankernel V1.06 ***********​

1. Upstreamed kernel to 3.18.140 + some extra patches, with more coming later.​
2. Added Wireguard support for better VPN performance compared to IPSec.​
3. Smaller fixes to the kernel zip files, improving compatibility with some models.​
4. Minor performance optimizations, shouldn't be noticeable to the end user.​
5. Now stable enough (at least the Stable version is) to be used as a daily driver.​

*********** Swankernel V1.00 ***********​

Initial release. Has the features from 1 to 12 on both versions, and from 1 to 3 on the Extreme version.​

​

Closing notes​

With V1.09, the kernel can now be flashed on basically any android version and should work out-of-the-box, although i didn't test it on stock roms at all and there are no reports of it working there, so it might not work on them.

From what i could gather during the multiple Pre-Beta tests, the battery life improved considerably over the kernel shipped by default with Lighthouse V20 and even more when compared to Lineage's stock kernel.

If you have any suggestion or idea that can possibly improve the kernel, do not hesitate to share, i will try to implement it when my time allows it. If there are any problems that only happen on this kernel, submit a log and i'll try to look at it.

The kernel's source code can be found here.

And last but not least, a special thanks for those that helped me even if indirectly:

• @xxseva44
• @npjohnson
• @askermk2000
• @lybxlpsv
• @flar2
• @osm0sis
• And many, many others

how did you add voltage control?

I tried both the stable and extreme versions of this kernel but they are both very unstable and buggy (tested on "stock" and LinageOS 1.18 rom). With no other options, I started making my own kernel for the LG H990 but I couldn't find anyone except you who has voltage control for the msm8996 chip. So my question is if you are willing to share the source/voltage control code with me?

 

[AShiningRay]

Can I use swan on oreo stock?

Not really, Swan is Lineage-based and also heavily updated on top of that, i doubt it would work reasonably well on stock roms.

 

[AShiningRay]

Using swan kernel makes the device snappier but i get random reboots on h918.
Not sure it ifs sdcard access related. I may test a bit more.

I will need some logs to get a good indication about what might be causing those random reboots. Does it always happen when you're using it? If so, it might be related to the CPU clocks causing spikes in power consumption during app switches and etc, seeing as mk2000 also faces that same problem on some devices like the H990DS. This seems to be a device issue and not a kernel one (undervolting a lot might mitigate that, but it's not ideal since it may introduce other stability problems in the case of this kernel's Extreme version).

If you have some time, and is running a rooted device, try getting Smartpack Kernel Manager or any other app that allows you to change CPU frequency, and drop the performance cores to 1824MHz or a bit lower and the low-power ones to around 1300MHz. After that those random problems should disappear, assuming the reboots are caused by power spikes.

 

[AShiningRay]

IS THIS KERNEL COMPATIBLE WITH LG G5 H830 & WHAT ANDROID VERSION IS SUPPORTED ?

In theory it might be compatible with pretty much any G5 variant supported by lineage, i just didn't compile a kernel for them since i don't have a G5 to test it so i'm hesitant on releasing something that might not even work in the end.

 

[AShiningRay]

how did you add voltage control?

I tried both the stable and extreme versions of this kernel but they are both very unstable and buggy (tested on "stock" and LinageOS 1.18 rom). With no other options, I started making my own kernel for the LG H990 but I couldn't find anyone except you who has voltage control for the msm8996 chip. So my question is if you are willing to share the source/voltage control code with me?

Any specifics to those instabilities and bugs, like logs or something? It would help immensely since my device isn't a H990.

As for the voltage control, here's the commit for voltage control on the extreme variant: https://github.com/AShiningRay/Swan...mmit/92aee4af63d325ace25cdb4cf66546a80258581d

There might be more commits related to that though, but this one is the main commit and should already get you the feature. However, i only really use it to check the cpu voltages in real time and finetune the undervolts on a newer kernel revision, since actual voltage control doesn't seem to work, and i never managed to get working voltage control on any of my qcom devices, be it Snapdragon 625/626, 435 or 820/821 (no matter the kernel, even other custom kernels with VC fail to undervolt my phones without triggering a reboot or crash in some capacity while undervolting them through the kernel's dt files works like a charm). If you're going to use it to undervolt while booted into the system, it might not work for you as well.

 

[TappedCeiling46]

Any specifics to those instabilities and bugs, like logs or something? It would help immensely since my device isn't a H990.

As for the voltage control, here's the commit for voltage control on the extreme variant: https://github.com/AShiningRay/Swan...mmit/92aee4af63d325ace25cdb4cf66546a80258581d

There might be more commits related to that though, but this one is the main commit and should already get you the feature. However, i only really use it to check the cpu voltages in real time and finetune the undervolts on a newer kernel revision, since actual voltage control doesn't seem to work, and i never managed to get working voltage control on any of my qcom devices, be it Snapdragon 625/626, 435 or 820/821 (no matter the kernel, even other custom kernels with VC fail to undervolt my phones without triggering a reboot or crash in some capacity while undervolting them through the kernel's dt files works like a charm). If you're going to use it to undervolt while booted into the system, it might not work for you as well.

Thank you for sharing. Hopefully I can use your code in combination with other code I've seen to get it working.

If you could add me on discord I think it would be easier than using the forum(TappedCeiling46 ΦωΦ#7651).
If not, could you explain where I can find the log file? I can send the logs along side the others bugs I know of so far.

At the moment I'm using the "stock" rom but If that's a problem I can try dual booting LineageOS ¯\_(ツ)_/¯

​

 

[AShiningRay]

Thank you for sharing. Hopefully I can use your code in combination with other code I've seen to get it working.

If you could add me on discord I think it would be easier than using the forum(TappedCeiling46 ΦωΦ#7651).
If not, could you explain where I can find the log file? I can send the logs along side the others bugs I know of so far.

At the moment I'm using the "stock" rom but If that's a problem I can try dual booting LineageOS ¯\_(ツ)_/¯

​

I hope so, fine-tuning voltages is way easier, and faster, to do when going through the GUI and without needing to recompile the kernel between tests.

I don't have a discord channel for communication, but i do have Telegram, if that one's available to you. But send me a PM with infos and such, since doing so right here is way too unsafe.

To get the logs, you can load up a terminal app on your phone, give it su privileges, then type "dmesg >> /sdcard/filename.log", or do the same commands but through adb.

And yeah... if you're using the phone's stock ROM by LG or any other rom that mainly modifies the stock one, i'm afraid bugs are to be expected since this kernel was only tested on custom roms, and is based on lineage's kernel sources.

 

[riverstyxxx]

VS995 says wrong version.

 

[AShiningRay]

VS995 says wrong version.

Huh, weird... the anykernel script is correct and checks for vs995. Did you crossflash your vs995 with any other variant's recovery? If not, might be a glitch in the script or something.

I don't really recommend flashing this kernel now that 4.4 is around and works almost as well, if not better than 3.18 most of the time... but if you're still interested, you can just open the flashable zip, open anykernel.sh and change the devicecheck prop to:
do.devicecheck=0

Assuming it's really a VS995, you won't have any issues.