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

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AShiningRay

Senior Member
Sep 1, 2021
145
65
Xiaomi Redmi Note 4
LG V20
with the official kernel in LOS 18.1 stereo sound for video recording is not working. I'm not sure if that is related to kernel, is it? I was notifying that sound was getting too loud when using hifi DAC. Low sound with audio recording. I have to set 400% in AudioRecorder (downloadable in f-droid.org) and yet it's weak. AFAIK for IR this kernel still has a problem with time lag after each shot and It does not add FM radio support, does it?
It's mostly identical to Lineage's kernel in regards to the device features, there's only some security updates and optimizations, so if you have any problem on stock lineage that isn't the charging over USB when connected to a PC (that one was fixed a while ago), it most likely will still happen here.

That audio problem could very well be kernel related for all i know, but will probably be something on the kernel-side device tree files and might require a lot o refactoring to achieve. Personally i don't think it's worth the hassle on 3.18.
 
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xxseva44

Senior Member
May 16, 2019
462
188
Canada
LG V20
Google Pixel 4a 5G
It's mostly identical to Lineage's kernel in regards to the device features, there's only some security updates and optimizations, so if you have any problem on stock lineage that isn't the charging over USB when connected to a PC (that one was fixed a while ago), it most likely will still happen here.

That audio problem could very well be kernel related for all i know, but will probably be something on the kernel-side device tree files and might require a lot o refactoring to achieve. Personally i don't think it's worth the hassle on 3.18.
Audio issue is in the dt, not kernel. It’s an issue with the levels set in the tasha xml.
 

JoeKis

Member
Apr 2, 2022
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0
Just installed it whit no problems but have problem with screen/display burning/ghosting. there was a fix I used previously with kernel audatory but there is no display section anymore. how can I fix this? I used gamma kernel before SwanKernel h990 lineage os 18.1
Does anybody else have this problem?
 

ROMSG

Senior Member
Just installed it whit no problems but have problem with screen/display burning/ghosting. there was a fix I used previously with kernel audatory but there is no display section anymore. how can I fix this? I used gamma kernel before SwanKernel h990 lineage os 18.1
Does anybody else have this problem?
Thats because KCAL was removed look for LiveDisplay under Setting/Display/LiveDisplay and drag the blue slider down by 10%, you can also drag the red and green back for more balanced color (about 5% or so).
 
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JoeKis

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Apr 2, 2022
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Thats because KCAL was removed look for LiveDisplay under Setting/Display/LiveDisplay and drag the blue slider down by 10%, you can also drag the red and green back for more balanced color (about 5% or so).
Tkanx! worked like a charm!! Any good tips for optimizing for battery time? like undervolting or any other method?
 

AShiningRay

Senior Member
Sep 1, 2021
145
65
Xiaomi Redmi Note 4
LG V20
Tkanx! worked like a charm!! Any good tips for optimizing for battery time? like undervolting or any other method?
Undervolt-wise the kernel has two flavors for that, Stable goes -60mV across the board while Extreme is -90mV, so one is perfectly stable on all phones that ran it while the other is prone to reboot on some of those so you should be fine on Stable already. You shouldn't notice any major difference between both unless you play games on it where the stronger gpu undervolt adds up.

And since you have kernel adiutor, you can do some extra tweaks to maximize battery life although it might impact the responsiveness a bit. Going into CPU->Governor tunables for both big and little clusters you should be able to set up_rate_limit to 3000 and down_rate_limit to 1000. This will make the cpu favor lower clocks but as i said before it might impact responsiveness.

Furthermore, setting I/O Scheduler -> Read-ahead to 128KB on both internal and SDcard (if you have one) will minimize wasteful read cycles whenever the scheduler reads useless info to try and "preload" some data for further use. This also reduces CPU usage slightly on those cases.

The rest is really minor like setting the Low Memory Killer profile to Very Light as it only really makes a difference in multitasking and setting Entropy to 64 Read, 256 Write.

After those, there's not much else you can do to improve battery life other than changing ROMs entirely.
 
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JoeKis

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Apr 2, 2022
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After 4 hour use I found a problem: battery draining fast even when off O-o . I didn't use an app or let something run in the background. my setup: Lineage Os 18.1 Latest LG V20 h990 (Dirty Santa) Battery original Newfrom LG (max 2 month). SwanKernel Stable. in an half hour from 60% to 20%
No battery drain with Gamma Kernel
 

AShiningRay

Senior Member
Sep 1, 2021
145
65
Xiaomi Redmi Note 4
LG V20
Well, first things first: Does it heat up at least mildly while idling with the screen off? Because if you have no background apps running, it might as well be Android 11 running iorap to prefetch some apps for faster loading, it tends to kick in whenever a big kernel or rom update happens and disappears after a while. The only way to really check what might be using the cpu is to use the "top" command through ADB or run it with su privileges on a local terminal, but i think lineage stopped building it a few months ago.

The kernel doesn't cause higher battery consumption by itself, it might be something external triggered by the massive upstream from gamma to swan.
 

xxseva44

Senior Member
May 16, 2019
462
188
Canada
LG V20
Google Pixel 4a 5G
After 4 hour use I found a problem: battery draining fast even when off O-o . I didn't use an app or let something run in the background. my setup: Lineage Os 18.1 Latest LG V20 h990 (Dirty Santa) Battery original Newfrom LG (max 2 month). SwanKernel Stable. in an half hour from 60% to 20%
No battery drain with Gamma Kernel
Sounds like a rogue app. And also, did you test gamma with your battery and the exact same setup with the same usage? Also fyi, new lg batteries don't exist. The "new" ones are old stock that have been sitting for the past 6 years. Pretty sure they stopped manufacturing them around 2019.
 

JoeKis

Member
Apr 2, 2022
5
0
Well, first things first: Does it heat up at least mildly while idling with the screen off? Because if you have no background apps running, it might as well be Android 11 running iorap to prefetch some apps for faster loading, it tends to kick in whenever a big kernel or rom update happens and disappears after a while. The only way to really check what might be using the cpu is to use the "top" command through ADB or run it with su privileges on a local terminal, but i think lineage stopped building it a few months ago.

The kernel doesn't cause higher battery consumption by itself, it might be something external triggered by the massive upstream from gamma to swan.
Like you said the draining stopped after a while. All good!
 

nostupidthing

Senior Member
Nov 1, 2012
1,124
271
i having problem with zoom on lineageos, want to flash this kernel to see if problem solves, i just download from https://androidfilehost.com/?w=files&flid=329155 (dec2021) and flash using twrp is ok right?

thx!

edit: ok it doesn't work, maybe cause i using lineageo os recovery, it says unsupported device

edit 2: ok twrp worked! thx!
 
Last edited:

AShiningRay

Senior Member
Sep 1, 2021
145
65
Xiaomi Redmi Note 4
LG V20
i having problem with zoom on lineageos, want to flash this kernel to see if problem solves, i just download from https://androidfilehost.com/?w=files&flid=329155 (dec2021) and flash using twrp is ok right?

thx!

edit: ok it doesn't work, maybe cause i using lineageo os recovery, it says unsupported device

edit 2: ok twrp worked! thx!
Welp, a bit late to answer that but i'm glad it worked! The flashable zip tends to spit out "unsupported device" when you try to flash a variant that doesn't correspond to the model it reports to the zip script.
 

itt533

Member
Nov 12, 2020
48
4
chennai
i flashed it right after installing the latest nightly LOS. It seems indeed it is consuming less and heats less, and, not sure about it but it seems faster in opening menus, and sliding screens.
As for the IR blaster, i was not able to get it working. But i did only a quick try with one app. Is there any app to test the IR receiver? indeed the lg v20 does both.

As for audio recording, it is same as with native kernel. The sound is weak when recording in stereo (mono is fine). The gain boosted to 400% in "audio recorder" makes it better but not as good as with stock kernel.
 

AShiningRay

Senior Member
Sep 1, 2021
145
65
Xiaomi Redmi Note 4
LG V20
i flashed it right after installing the latest nightly LOS. It seems indeed it is consuming less and heats less, and, not sure about it but it seems faster in opening menus, and sliding screens.
As for the IR blaster, i was not able to get it working. But i did only a quick try with one app. Is there any app to test the IR receiver? indeed the lg v20 does both.

As for audio recording, it is same as with native kernel. The sound is weak when recording in stereo (mono is fine). The gain boosted to 400% in "audio recorder" makes it better but not as good as with stock kernel.
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.

And that low audio volume during recordings is very likely to be related to the tasha (Snapdragon 820 sound card name) xml configs in the device dts and hence is more of a ROM problem, as @xxseva44 pointed out above.
 

itt533

Member
Nov 12, 2020
48
4
chennai
I've already done the hardwork of figuring out what does what. Guide
ok. I initially tried with ghost commander but no luck. I finally took solid explorer as per your suggestion and editing /vendor/etc/mixer_paths_tasha.xml worked.

Well I modified the file following your directions but it didn´t change the low recording volume with "audio recorder" when setting stereo mic.
 

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    SwanKernelLogo.png


    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:
    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
    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):
    Screenshot_20211025-185046214.jpgScreenshot_20211025-193015235.jpg

    Not very impressive, until you consider the battery currently powering it:
    Screenshot_20211025-185057599.jpg

    CPU/GPU Performance:

    CPU performance according to Geekbench 5.4.1 (there is some minor variance of about 15-21 points in multithread):
    Screenshot_20211025-195919247.jpg

    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):
    Screenshot_20211025-194844892.jpg

    GPU general performance on GFXBench 5:
    Screenshot_20211025-205142387.jpg

    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):
    Screenshot_20211025-205621339.jpg

    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

    *********** 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:

    3
    Alright, with the recently released V1.09 i now deem this kernel EOL, or at least, its 3.18 version since i will now be focusing on porting 4.4 to the LG MSM8996 family of devices alongside @askermk2000, since that tree is still being actively developed by linux-stable and also contains a slew of general improvements to both security and performance over the current 3.18 source that i don't think can be further optimized or fixed. The IR is still in need of fixing, but at this point i think starting fresh from a clean source might prove more beneficial to solve it than looking around the entire kernel source again. But if any issues with that new release crop up, do tell me and i will try to provide support.
    2
    The ir is most likely consumer ir related so, we'll have to tweak it until it starts working
    2
    Hello when I try to flash Swan-H918-Stable.zip on an h918 I get "Unsupported device. Aborting..."
    Huh... that's strange. I must have messed something up during the anykernel zipping procedure on that model. I'm almost pushing an update to the kernel, so i'll be back in a while with a fix for that.

    Edit: Yeah, it was something in the script file, i forgot to change the H910 to H918 on that specific variant flashable. Sorry for that.
    I just pushed the file with the fixed script for all the models i checked. If you could test that, i would appreciate it.
    2
    Wow this Kernel is amazing! Thermals improved massively and the V20 runs much faster and smoother now. I'm able to do things that were impossible before like browse the web while watching Youtube. Duck Duck Go used to stutter when clearing my data, now it does it smoothly.

    Everything is faster while somehow the phone runs much colder. I still need to test my GCam and if I can take a few photos without crashing.

    I'm using the H990DS with Lineage 18.1. During the throttle 1 core stayed at 70C while others were around 60-65C (I'm using a thermal pad).

    wMdy5DJ5brSFPd05n_mBKCwOhYVDJR6Vjzx0jZqG2CjSu49-ox1wbRIeKsg2K6bgNJtjgt6Wr5Vyz8wSr7gAFIMd4jDQeu067ZUeTe5swd1rRFwx0s6es5YfIWKimlNZLKGTHYdigwLbnzYgtBaOhIPXXQz1wrG0BCuzCI4mjY7A-4WaV3ek5ypESqSq_2JuSOVVNcul0m0d9VnlLB2tnlsBxuyhm5ZDiMi6L2BtMxJHtlFiCnCYLESRdCtuC-0zm5IZ6TgljsIbKyRNWpn7H8y_aGrq7AZ2z_G65lsKzAUuMVAFdCcmcOvBJ4QUL8Zzj_c_Vk7Ts1WPptem2Htmmyrp8AZ33cnis4tchiloGvkmbw5BLNY6GOzWuegjkM-hUFtGVwBs2O0lDD9JVQZSrP7xjedS8sAdYiVETEdVzKouF0d8lutIp7epGRFjWGD1jaTtd9-l3P9vVxYo_FJ5KRtJ-tlx-2FNGt1nj8OFQddH6vUBFxza_tZDV5SrJvcUDtcRe52ZWgUF2BQ8u5fZIh7ErO1da0f1kXv0s4-LlAyaZ6YXx0rIJZrEMEwTS7WwCOsnErw2ec_Hz6mxPK4jO4OPPee_m1LS1EQKN5A1-OLaf1JwqUrNMSU98IgAcF-AVSF7kY-Am7z8U_BJWAYxtc8yyFA42GQFRTMhIncu8KaShmOzBX_lazgHyjwJU477CYu_ES9uX6DCEQwT4jcklOcneQ=w497-h937-no

    I bought a V60 as a replacement but now I don't even need it anymore, it's a shame I can't refund it now. Amazing job and thanks for all the devs keeping this phone alive. Might try Lighthouse later but I'm lazy to back up all my data for migration.
    Thanks! Happy to know the kernel is being useful to others as well. And a bit of a spoiler (xxseva already hinted at it in a few places, lol), but there's definitely a lot more coming for the V20, G5 and G6, although i can't share many details about it nor a ETA of when it will arrive. But if/when it arrives, you can expect Android 12 with a kernel that's essentially the best parts of Swan and mk2000 mashed together.