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

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KouaV1

Senior Member
Jun 22, 2015
148
20
LG V60 ThinQ
I used the stable kernel and sadly seems like the undervolts are too low, my antutu scores are lowered by around 20k points compared to using that mk2000 kernel on raft custom rom
 

KouaV1

Senior Member
Jun 22, 2015
148
20
LG V60 ThinQ
You're complaining about performance reduction, on an undervolted kernel focused on battery life and efficiency...?
wasnt complaining, pointing it out, with proper undervolt it should not have alot of reduction in performance as i had thought he put on that changelog without affecting performance alot but it did affect it by alot.
 

AShiningRay

Senior Member
Sep 1, 2021
144
64
Xiaomi Redmi Note 4
LG V20
wasnt complaining, pointing it out, with proper undervolt it should not have alot of reduction in performance as i had thought he put on that changelog without affecting performance alot but it did affect it by alot.
You're right, proper undervolting shouldn't reduce performance, and it doesn't. Your performance reduction doesn't come from the undervolts, instead it's probably coming from the tweaked schedutil rates that focus a lot more on battery life than raw performance. My adjustments were meant to have a minimal impact in responsiveness and such, not benchmarks (which aren't really a great indicator of the device's performance by themselves, especially antutu).
 

KouaV1

Senior Member
Jun 22, 2015
148
20
LG V60 ThinQ
You're right, proper undervolting shouldn't reduce performance, and it doesn't. Your performance reduction doesn't come from the undervolts, instead it's probably coming from the tweaked schedutil rates that focus a lot more on battery life than raw performance. My adjustments were meant to have a minimal impact in responsiveness and such, not benchmarks (which aren't really a great indicator of the device's performance by themselves, especially antutu).
ah i see where its coming from, Thanks for the clarification on the kernel
 

AShiningRay

Senior Member
Sep 1, 2021
144
64
Xiaomi Redmi Note 4
LG V20
ah i see where its coming from, Thanks for the clarification on the kernel
No problem. It's just that i built this kernel to mitigate this phone's tendency to easily get hot so i ended up sacrificing some sustained performance along the way in an effort to improve battery life and temps.

Thankfully that's not an issue anymore on the new 4.4 kernel (which is a merge of this and mk2000) that's being bundled on the latest Android 12 betas, so it is both more efficient and faster than 3.18 kernels so far.
 

KouaV1

Senior Member
Jun 22, 2015
148
20
LG V60 ThinQ
No problem. It's just that i built this kernel to mitigate this phone's tendency to easily get hot so i ended up sacrificing some sustained performance along the way in an effort to improve battery life and temps.

Thankfully that's not an issue anymore on the new 4.4 kernel (which is a merge of this and mk2000) that's being bundled on the latest Android 12 betas, so it is both more efficient and faster than 3.18 kernels so far.
no problem, after a couple hour usage i noticed it, thanks
 

yesimxev

Senior Member
May 8, 2017
406
159
IR is still not working on LOS18.1. Which kernel driver is responsible? I'd try to roll back to stock oreo driver see if that helps
 

AShiningRay

Senior Member
Sep 1, 2021
144
64
Xiaomi Redmi Note 4
LG V20
IR is still not working on LOS18.1. Which kernel driver is responsible? I'd try to roll back to stock oreo driver see if that helps
It's not any of the IR drivers, they're identical to Gamma's and IR works there. The current hypothesis we have on 4.4 is that some upstream broke communications with the IR driver, and reverting that is far more complicated. If you really want to try your hand at that, i'd start by checking for differences between gamma's "gamma-oreo-stable"(working IR) and "gamma-pie" (borked IR just like any other kernel) branches in their repo.
 

yesimxev

Senior Member
May 8, 2017
406
159
It's not any of the IR drivers, they're identical to Gamma's and IR works there. The current hypothesis we have on 4.4 is that some upstream broke communications with the IR driver, and reverting that is far more complicated. If you really want to try your hand at that, i'd start by checking for differences between gamma's "gamma-oreo-stable"(working IR) and "gamma-pie" (borked IR just like any other kernel) branches in their repo.
Oh so it's ROM level, and Gamma ROM works fine? Confirm and I'll dive into it soon. The other mystery compared too that some of the external wireless drivers are causing the OS to crash on boot. Whereas it was working fine on oreo. Also if they are enabled as modules they are fine when loaded and works
 

AShiningRay

Senior Member
Sep 1, 2021
144
64
Xiaomi Redmi Note 4
LG V20
Oh so it's ROM level, and Gamma ROM works fine? Confirm and I'll dive into it soon. The other mystery compared too that some of the external wireless drivers are causing the OS to crash on boot. Whereas it was working fine on oreo. Also if they are enabled as modules they are fine when loaded and works
No, it's not the rom either. Simply swapping any 3.18 kernel by gamma-oreo (gamma is a custom kernel, not a ROM) already makes IR work on any rom made for those older kernels.

The upstream in question is on the kernel side, such as bumping from 3.18.71 to 3.18.103 for example. Tons of code gets updated (including qualcomm's), and some of it can cause a few unintended and obscure issues... which seems to be the case for IR, considering it also fails to work on certain gamma branches.

As for the external wireless drivers, it can be a case of them not being built with the kernel at all to begin with. Swan (as well as mk2000, not sure about gamma) gets built with the least amount of bloat possible, so they're bound to not have those drivers actually present. LG's stock kernel on the other hand has a slew of additional kernel CONFIGs(those are basically switches dictating what's gonna be built with the kernel) and those could be a part of them.
 

yesimxev

Senior Member
May 8, 2017
406
159
No, it's not the rom either. Simply swapping any 3.18 kernel by gamma-oreo (gamma is a custom kernel, not a ROM) already makes IR work on any rom made for those older kernels.

The upstream in question is on the kernel side, such as bumping from 3.18.71 to 3.18.103 for example. Tons of code gets updated (including qualcomm's), and some of it can cause a few unintended and obscure issues... which seems to be the case for IR, considering it also fails to work on certain gamma branches.

As for the external wireless drivers, it can be a case of them not being built with the kernel at all to begin with. Swan (as well as mk2000, not sure about gamma) gets built with the least amount of bloat possible, so they're bound to not have those drivers actually present. LG's stock kernel on the other hand has a slew of additional kernel CONFIGs(those are basically switches dictating what's gonna be built with the kernel) and those could be a part of them.
Got it now, can you point me to the latest working exact version please? Or even, does IR working gamma kernel potentially work with LOS18.1?
 

AShiningRay

Senior Member
Sep 1, 2021
144
64
Xiaomi Redmi Note 4
LG V20
Got it now, can you point me to the latest working exact version please? Or even, does IR working gamma kernel potentially work with LOS18.1?
AFAIK, the safest and surest way to get a gamma build with working IR is to build it yourself, as i couldn't find any kernel builds out there that didn't lead to dead links, or broken IR.

The repo (and branch) containing the version with working Infrared, that i tested myself and can confirm it was working, is here:

From my testing, the gamma-oreo-stable branch is the newest kernel that still has it working.

Also yes, it will work with LOS 18.1 assuming no changes were made to libcir and other rom-side IR blobs ever since i tested it.
 
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yesimxev

Senior Member
May 8, 2017
406
159
AFAIK, the safest and surest way to get a gamma build with working IR is to build it yourself, as i couldn't find any kernel builds out there that didn't lead to dead links, or broken IR.

The repo (and branch) containing the version with working Infrared, that i tested myself and can confirm it was working, is here:

From my testing, the gamma-oreo-stable branch is the newest kernel that still has it working.

Also yes, it will work with LOS 18.1 assuming no changes were made to libcir and other rom-side IR blobs ever since i tested it.
Thank you! Really appreciated. Yes I'll build as I need to add NetHunter patches + configs
 

yesimxev

Senior Member
May 8, 2017
406
159
AFAIK, the safest and surest way to get a gamma build with working IR is to build it yourself, as i couldn't find any kernel builds out there that didn't lead to dead links, or broken IR.

The repo (and branch) containing the version with working Infrared, that i tested myself and can confirm it was working, is here:

From my testing, the gamma-oreo-stable branch is the newest kernel that still has it working.

Also yes, it will work with LOS 18.1 assuming no changes were made to libcir and other rom-side IR blobs ever since i tested it.
What is the defconfig for h990? lineage_h990 seems dodgy
 

AShiningRay

Senior Member
Sep 1, 2021
144
64
Xiaomi Redmi Note 4
LG V20
What is the defconfig for h990? lineage_h990 seems dodgy
It should be "lineageos_h990_oxavelar_defconfig" seeing as the defconfig i used for mine was "lineageos_h910_oxavelar_defconfig".

And they look weird because oxavelar added the gamma tweaks into each defconfig manually instead of using a separate file for gamma overrides, it's the same case for the other variants as well.
 

yesimxev

Senior Member
May 8, 2017
406
159
It should be "lineageos_h990_oxavelar_defconfig" seeing as the defconfig i used for mine was "lineageos_h910_oxavelar_defconfig".

And they look weird because oxavelar added the gamma tweaks into each defconfig manually instead of using a separate file for gamma overrides, it's the same case for the other variants as well.
I see, then it's not the defconfig. Last one, any recommended toolchain? I have an error which I never seen, will copy here when I get home
 

yesimxev

Senior Member
May 8, 2017
406
159
I tried 3 different toolchain, no modifications yet.

1673703845021.png
 

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  • 1
    Got it now, can you point me to the latest working exact version please? Or even, does IR working gamma kernel potentially work with LOS18.1?
    AFAIK, the safest and surest way to get a gamma build with working IR is to build it yourself, as i couldn't find any kernel builds out there that didn't lead to dead links, or broken IR.

    The repo (and branch) containing the version with working Infrared, that i tested myself and can confirm it was working, is here:

    From my testing, the gamma-oreo-stable branch is the newest kernel that still has it working.

    Also yes, it will work with LOS 18.1 assuming no changes were made to libcir and other rom-side IR blobs ever since i tested it.
    1
    I tried 3 different toolchain, no modifications yet.

    View attachment 5810269
    Try getting my build.sh script from Swan's repo and using it to build gamma. Not sure how i build it a while ago, but i'm pretty sure i also used it to some capacity... you'll need to make some adjustments to the script though, such as toolchain locations and defconfig names.
    1
    Yes, there's been some rather large camera updates in the kernels and roms since gamma-oreo. Gamma-pie has the most important ones if i'm not mistaken (voltage, gpio and clock adjustments), but i don't remember if IR works well there. Not sure if that will be a bother to you but... could you test those two on gamma-pie? We're in the process of fixing IR on 4.4 and even gamma seems shaky at best with camera and IR.
    Pie works like a charm. I couldn't test everything, but the camera and IR are working 🎉
  • 9
    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.