[WIP] Enhanced kernel for CherryTrail devices (tablets/convertibles) - 4.14 - Chromebooks

Hi, there!
Now that we can use Project Croissant to get ChromeOS running or non-Chromebook devices, what is missing is a better kernel for improved compatibility.
Thanks to the threads by @nabil2000 I was able to successfully build a chromeos-4.14 kernel that boots on my test device (Lenovo MIIX320-10ICR - Z8350 processor) using a CONFIG from FydeOS 5.31 with most hardware enabled (WiFi, Bluetooth, sound), but it has the same issue as latest ATB builds: it freezes after a while. This doesn't happen with latest FydeOS or CloudReady builds (CloudReady bought FlintOS so I guess they are using some of their code now), so my guess if that their kernels have some patches that aren't included in the Chromium git. FydeOS is open-sourced only for RaspberryPi and TinkerBoard, there are no sources available for the PC or VMWare versions (PC version is not open source as many say, so be aware).
I already have some ideas to make the trackpad as well as the battery meter and brightness work, but it is not useful if the kernel isn't as stable as FydeOS (virtually no freezes or crashes once booted). I have already checked, and the issue is not the intel_idle.max_cstate issue that plagued most BayTrail/CherryTrail devices in the past (using value 1 doesn't change anything).
So any ideas how to get FydeOS kernel source? Patches to make the current chromeos-4.14 kernel stable?
UPDATE: As @nabil2000 reported, it seems that FydeOS is not willing to release their kernel source. But it is possible to get kernel config from v5.31 using configs.ko module, which is missing in the next version (v6.0). Using FydeOS v5.31 as base it is possible to build a very stable kernel for CherryTrail devices.
Thanks

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Installation v71/v72 - kernel 4.14
FydeOS has the best support for the MIIX320-10ICR, with some caveats:
It will boot to a black screen, but you just need to wait until it finishes loading the hit Ctrl+Alt+Fn+F2, the screen will blink and then hit Ctrl+Alt+Fn+F1 to go back to ChromeOS (for some reason, the developer shell is blank in 5.31 but it seems to work fine on 6.0). Use Ctrl+Shift+Fn+F3 to rotate the screen manually;
WiFi works out of the box, Bluetooth is detected but audio does not work (Chromium misses a library for audio over Bluetooth);
Sound works too, but you need to install some UCM files (more about this later);
Camera does not work, and the trackpad works very well, with gestures, but does NOT click (tap to click work with a custom conf file, see below - the trackpad actually sends two events when clicking the physical button, as some Windows devices do, and this doesn't work with cmt driver).
First I tried to build the ChromeOS file using the chromium.img from FydeOS v5.31. It booted fine and I was amazed to see the ChromeOS logo and Google enrollment, but PlayStore setup didn't finish (low space?) and there was no way to install it to another driver: many GPT errors and the installer failed...
Then I tried to do everything on place:
Booted to FydeOS on USB drive;
As I could not get to the dev shell in v5.31, I had to login then use crosh and shell, then installed it on a second external disk (120GB SATA on USB, /dev/sdb):
PS: your device may be a different one, check the correct device name using "lsblk" or "fdisk -l" and be aware that this installation erases the whole disk!
Code:
sudo chromeos-install --dst /dev/sdb
After installing, I have used option 2A from GitHub page (very detailed, thanks!) with the script, soraka (or pyro) and caroline recoveries (both versions 11151.113 = v71) on another disk:
PS: FydOS v5.31 kernel does not have support to VTPM_PROXY, while v6.0 does, it means you cannot use swtpm.jar with FydeOS v5.31 and chromefy. For nocturne or Android Pie ARC, you must use FydeOS v6.0, otherwise ARC won't work.
Code:
sudo bash ./chromefy.sh /dev/sdb recovery.bin caroline.bin
Answered YES to use the local installation, YES to resize partitions and NO in the end to keep SELinux as enforced (it may work fine if you keep it to enforced with nocturne recovery tho when using FydeOS v6.0);
Rebooted using the final installation, logged in and everything seemed fine, but then Play Store would not show installed apps even after a reboot, so I tried a powerwash and it seems it fixed the issue, now it seems to be working fine.
Original post: https://forum.xda-developers.com/showpost.php?p=78891386&postcount=729

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Post installation fixes v71/v72 - kernel 4.14
1. Sound
You need to install UCM files using linuxium-install-UCM-files.sh script after remounting rootfs as RW.
Code:
sudo remount -o rw,remount /
sudo bash ./linuxium-install-UCM-files.sh
2. Headphone jack
You must send this quirk to the rt5645 module when loading it, so while rootfs is still RW, as root add a file named "miix320.conf" to /etc/modprobe.d with this line:
Code:
options snd_soc_rt5645 quirk=0x1030
PS: if you have used the correct UCM files then the audio should change between speakers and headphones, but not mic. To enable internal mic:
Code:
sudo alsaucm -c chtrt5645 set _verb HiFi set _enadev DMic
and to enable mic from headset:
Code:
sudo alsaucm -c chtrt5645 set _verb HiFi set _enadev HSMic
3. Tap to click with trackpad
While rootfs is still RW, as root add a file named "50-mixx320.conf" to /etc/gestures:
Code:
Section "InputClass"
Identifier "MIIX320 conf"
MatchUSBID "048d:*"
MatchIsTouchpad "on"
MatchDevicePath "/dev/input/event*"
Option "Tap Minimum Pressure" "1"
EndSection
PS: for this to work, make sure "tap-to-click" is enabled in trackpad section of system Settings. If you have another device, use "dmesg | grep input:" with "lsusb" to find your device USB id instead of "048d:*".
Still needing fixes:
- chrome://flags is blank for some reason, so any special flags should be added manually to "chrome_dev.conf" instead;
- Trackpad physical button click;
- Brightness control;
- Battery meter;
- Rotation;
- Automatic change between tablet/desktop modes;
- Cameras (hardly they will work as they rely on ATOMISP, which was abandoned and does not work even on newest kernels).
Original post: https://forum.xda-developers.com/showpost.php?p=78978577&postcount=757

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reserved

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Good news! With chromeos-4.19 it is possible to fix most problems:
- trackpad button click;
- battery meter;
- accelerometer sensor module is loaded, it needs to be tested;
- possibly brightness can be fixed too.
Using FydeOS v5.31 kernel config as base I could get a very stable build, but it broke loading ARC somehow, and I have no idea why. Maybe it's a permissions/signatures issue? I will try to run chromefy again, with the new kernel already in place to see if it works.

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lfom said:
Good news! With chrome-4.19 it is possible to fix most problems:
- trackpad button click;
- battery meter;
- accelerometer sensor module is loaded, it needs to be tested;
- possibly brightness can be fixed too.
Using FydeOS v5.31 kernel config as base I could get a very stable build, but it broke loading ARC somehow, and I have no idea why. Maybe it's a permissions/signatures issue? I will try to run chromefy again, with the new kernel already in place to see if it works.
Click to expand...
Click to collapse
Nice to see you do some kernel work.
Care to share link to Chromium OS Kernel 4.19 source code, I would like to get a crack at using menuconfig to add drivers..

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nabil2000 said:
Nice to see you do some kernel work.
Care to share link to Chromium OS Kernel 4.19 source code, I would like to get a crack at using menuconfig to add drivers..
Click to expand...
Click to collapse
Sure. I should post a full guide as soon as I get ARC working without issues, the new kernel is awesome.
I have used the same base procedure as you did:
https://github.com/dnschneid/crouton/wiki/Build-chrome-os-kernel-and-kernel-modules
I then cloned (duplicated) the kernel source (chromeos-4.14) so I could then checkout the newer version while keeping the old one:
Code:
$ cd ~/kernel_new
$ git reset --hard origin/chromeos-4.19
PS: I am building on Xenial (not chroot), so I had to install libssl-dev in order to successfully build it.

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lfom said:
Sure. I should post a full guide as soon as I get ARC working without issues, the new kernel is awesome.
I have used the same base procedure as you did:
https://github.com/dnschneid/crouton/wiki/Build-chrome-os-kernel-and-kernel-modules
I then cloned (duplicated) the kernel source (chromeos-4.14) so I could then checkout the newer version while keeping the old one:
Code:
$ cd ~/kernel_new
$ git reset --hard origin/chromeos-4.19
PS: I am building on Xenial (not chroot), so I had to install libssl-devel in order to successfully build it.
Click to expand...
Click to collapse
I am a lazy billy - thanks - I like copy & paste, & think as little as I can afford

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Could you help me patching it on my GPD pocket?
it uses cherry tail
https://forum.xda-developers.com/ha...gpd-pocket-t3928828/post79496417#post79496417
thank you