[Letux-kernel] How to build LetuxOS Android Kernel for LetuxOS Replicant 4.2?

[Andreas Kemnade]

On Sat, 29 Jun 2019 09:20:16 +0200
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> > Am 29.06.2019 um 08:37 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> > 
> >   
> >> Am 28.06.2019 um 19:38 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> >> 
> >> Hi,
> >>   
> >>>> 
> >>>> find -name "*.ko" -exec mv \{\} /path/to/system/lib/modules \;  
> >>> 
> >>> That is what I had tried first but it did not load any module...
> >>> Maybe it needs a special depmod to be run.
> >>>   
> >>>> not worth searching for.  
> >> 
> >> Looks as if I have found something:
> >> 
> >> https://android.googlesource.com/device/asus/fugu/+/b01b7fd/AndroidKernel.mk#102
> >> 
> >> This does the "find -exec cp" but then runs a depmod. KERNEL_FAKE_DEPMOD seems to be a (broken?) symlink to help to create proper file names.
> >> 
> >> And, we might have an AndroidKernel.mk as well.  
> > 
> > I haven't found one but there is load_modules.sh:
> > 
> > 	http://git.goldelico.com/?p=letux-replicant-device.git;a=blob;f=rootdir/load_modules.sh;h=73c6c9255b655207ec422a3590646eb67cb769a6;hb=refs/heads/replicant-4.2-v2
> > 
> > This script seems to modprobe everything which is needed - at least in Letux-replicant-4.2-v2
> > 
> > I have done some more checks on the 4.6 kernel (Linux localhost 4.6.0-letux+ #1 SMP PREEMPT Sat Jun 18 21:04:58 CEST 2016 armv7l GNU/Linux) that works.
> > 
> > * the above mentioned script is installed in /system
> > * kernel modules are loaded
> > * there is no sd8686_v8_helper.bin at all and therefore, loading WiFi firmware must fail...
> > * if I build work/lukas/android-4.10 and flatten the kernel modules and patch it over the replicant-kernel-4.6 rootfs I can boot!
> > * there is only a handful of kernel modules automatically loaded
> > * but if I manually run /system/load_modules.sh the panel starts working!
> > * not fully. touch is not working, a Linux console cursor is blinking and the home button is missing
> > * WiFi is still not working, but that is the missing firmware in the replicant-kernel-4.6 rootfs
> > 
> > So I may be able to create an SD card with replicant-kernel-4.10 and patch in a newly compiled kernel potentially with fixes.
> > Hopefully the kernel panics will go away and WiFi come up...
> > 
> > Since I have uploaded the kernel to the downloads server makesd should now be able to create a new mixed system:
> > 
> > 	makesd replicant -r http://download.goldelico.com/letux-replicant/4.2/20170423-kernel-4.10-replicant.tbz -kboot http://download.goldelico.com/letux-kernel/work/lukas/android-4.10-replicant/uImage -dboot http://download.goldelico.com/letux-kernel/work/lukas/android-4.10-replicant/device-trees.tbz -m http://download.goldelico.com/letux-kernel/work/lukas/android-4.10-replicant/modules.tgz  
> 
> First test:
> 
> * does boot
> * modules are not properly loaded
> * running /system/load_modules.sh loads some more modules
> * modprobe omapdrm remports missing symbols
> * running depmod (busybox) seems to fix something :)
> * then, /system/load_modules.sh loads the missing modules and the display initializes!
> * depmod -n takes quite some time to start printing the module lists and dependencies and finally segfaults
> * there is no modules.dep anywhere except /system/lib/modules/modules.dep.bb
> * ah well, we also have /system/xbin/depmod which should be used - but that one also segfaults :( Maybe too many or too big kernel modules?
> * there is a blinking console cursor in the middle of the screen
> * charging works fine - did report that battery is getting low (except not automatically activating screen backlight), played a sound
> * plugging in the USB cable made the battery start charging - with 100mA only... I had to do echo 800000 >/sys/class/power_supply/twl4030_usb/input_current_limit to really get it charging

fixed in commit
commit 7831c02e7ec2a40e6b15065441234509cc49a8c3
Author: Andreas Kemnade <andreas at kemnade.info>
Date:   Thu Apr 27 21:37:48 2017 +0200

    load_modules.sh: add parameter allow_usb=1
    
    usb current was limited to 100mA, fix that


but not in the image... I guess I really should try to rebuild it.

Regards,
Andreas