[Gta04-owner] We need an Android kernel

[Dr. H. Nikolaus Schaller]

Am 17.07.2013 um 14:38 schrieb Paul Kocialkowski:

> Le mercredi 17 juillet 2013 à 13:48 +0200, Dr. H. Nikolaus Schaller a
> écrit :
>> So I would conclude that we *can* run Android on top of our 3.7 neil-plus
>> kernel [1]. We just need to configure the Android extensions and add the init ramdisk.
> 
> I just tired with a proper ramdisk (initramfs). So the UI starts but
> input needs to be corrected (I think I know how).

You mean touch screen orientation? I think this should be corrected/calibrated
somehow in user space so that we can keep the tsc2007 driver untouched.

It should also be better because it does some dejitter.

> The 3.7 kernel lacks
> Android USB Gadget support (the code is missing).

Ok, that may be one of the patches that are not yet in mainline Linux.
I have expected that we would not get 100% for free...

> Also, it seems that
> OTG doesn't work.

Hm. That one works with Debian. Maybe it needs additional config?

@Neil: ?

> When doing suspend/resume cycles, I encountered
> various segfaults (one was about I2C, another one about GPIO) that
> required me to reboot the phone.

Maybe but we should fix them in the long run in mainline - or they come
back every major version step...

But AFAIK QtMoko is using the same kernel basis for a while and does
not show these issues. At least they don't surface.

Well, Android may "test" different kernel features than QtMoko...

> That's exactly the sort of things that
> wouldn't happen with a TI kernel.

I have made the same experience with the 2.6.32 hw-validation kernel.

This was derived from the BeagleBoard XM kernel and did have tons
of TI patches inside. The problem was that there was no migration path
to a newer kernel and we had to backport any new feature that was interesting
and asked for which became quite frustrating since patches never applied
cleanly. And, it did lack proper power management.

It also took quite some time to bring the neil-plus kernel to almost the same
feature set (TVout is still missing). But it was and will be much easier to add
new features.

> I can keep going by adding Android USB Gadget support from where I can
> find it. I think GNUtoo already did that in the past on Neil's 3.7
> kernel, with more or less valid results.
> 
> Let's keep going with that idea for now.

Generally I think we now have a great basis to continue from!

As soon as you are happy with it, please push to the repo so that I (we)
can sync and try ourselves...

BR,
Nikolaus