[Gta04-owner] [ANN]: Kernel progress

Mon Oct 7 15:28:38 CEST 2013

Am 07.10.2013 um 14:22 schrieb Alexander Rumyantsev:

> Hello
> 
> I again and again try get an answer:
> We interested in not in latest kernel version, but stable version.
> For Android propose a good example is 3.0,

I have done this twice to decide to stabilize on a certain version of a kernel. And after
half a year you are done, but the majority of users asks why you still have such an old
kernel...

Then, you start over with a newer stable kernel and start to forward-port a very big
bunch of patches since the kernel developers have introduced half a million patches
in the mean time. You have to debug all this and patch patches...

It take another half year. And people ask again why you have such an old kernel...

All this is no problem if we have enough people to work at several ends at the
same time and come up with a patched kernel in let's say 4 weeks.

But we have only a very small group of kernel developers.

> in our situation may be 3.7 is suitable version.  

No, e.g. Ubifs in NAND is inherently not stable in 3.7 but in 3.12...
This means you can't flash 3.7 into NAND. Or have to find out what needs to be
changed.

BTW, I got the impression that 3.12 boots twice as fast since it can defer probing
and retry later instead of waiting until every resource becomes available.

So a 3.12 kernel will be better than any 3.0 or 3.7.

>> 3.12-rc4 has been merged.
>> 
>> This fixes an issue with the hmc5883l driver.
>> 
>> Additionally, we have improved our '-plus' patches:
> 
> Is it possible to apply "improved '-plus' patches" to 3.7

You can always go back to http://git.goldelico.com/?p=gta04-kernel.git;a=shortlog;h=refs/heads/3.7-neil-plus
and start backporting. But IMHO this is waste of efforts.

The main reason why we work on linus/master is that we want to get as many things
into upstream so that they will be automatically maintained by the kernel
developer's community. This saves a lot of work, but is impossible to start on 3.7.

At the moment you may not see an immediate benefit, but assume we are working
on 3.17. Then you can still decide to checkout our 3.13 to 3.16 if it is more stable.

But you can be sure that we won't loose features after ~3.13 any more because we
are feature-complete and have to test&check it only. And stabilize even more.

What also becomes possible is if e.g. 3.12 becomes the next long-term kernel,
we can easily maintain a branch for 3.12.1 etc. and merge their latest patches
every one or two weeks. This is almost effortless - since it rarely will break anything.

Then we will have both - participate in the newest developments at maintainable
complexity (Linus submits new -rc ca. once a week) and have stable long term
kernels.

BR,
Nikolaus

> 
> 
> Alexandre.
> 
>> * TVout is working again
>> * itg3200 is working again
>> * Bluetooth is working again
>> * detection of 1 GHz CPUs improved
>> 
>> So we are not far away from being as function complete as the 2.6.32-hw-validation kernel was.
>> 
>> We have only these road-blocking issues left over:
>> * PVR/SGX kernel driver is not up to date (and therefore disabled)
>> * WiFi does not power down if not used; and we see a kernel exception on ifconfig wlan0 up
>> * Power management improvements
>> 
>> The PVR/SGX issue has been postponed until TI releases a new SDK for 3.12 (because there are significant changes in the /proc API).
>> 
>> The WiFi issue has been identified to be in the interworking of the sdio driver and libertas. For some unknown reasons it does not automatically power down WiFi any more (to be more precise: it powers it down once after detecting which card is connected and before deciding to load libertas, but not after loading libertas).
>> 
>> This all stops us from debugging/improving power management of 3.12 because we can't turn off WiFi...
>> 
>> BR,
>> Nikolaus
>> 
>> 
>> Am 30.09.2013 um 12:45 schrieb Dr. H. Nikolaus Schaller:
>> 
>>> And 3.12-rc3 is merged!
>>> 
>>> The most significant changes with significance for the GTA04 appear to be in the omap-dss system.
>>> 
>>> We have also integrated the linear charging patch.
>>> 
>>> And, we have discussed with the omap-dss maintainer how to get back the TVout. This turned out to be quite complex since we are the first to use a video amplifier - and therefore need to add a driver for it to setup the tv-out pipeline. And, we will have to enhance the VENC driver to add some rarely used mode setting (for using the external amplifier). This all was previously done in the board file using some hooks - but the hooks have been removed to make the drivers ready for device tree.
>>> 
>>> BR,
>>> Nikolaus
>>> 
>>> Sorry for top-posting, but this is like the git log - the most recent changes come first...
>>> 
>>> 
>>> Am 24.09.2013 um 11:05 schrieb Dr. H. Nikolaus Schaller:
>>> 
>>>> I have merged 3.12-rc2 from linus/master [1,2]
>>>> 
>>>> From the commit messages I think this fixes some parts for the iio drivers (bma180, hmc5883) and something in the EHCI.
>>>> 
>>>> And Marek has fixed the display driver and the TVout configuration. So now we have the display back again and the TVout is not far from working again, as it was last time in the 2.6.32 kernel. Thanks!
>>>> 
>>>> Still open is the auto-power control of WLAN/Bluetooth and GPS. And ITG3200, HMC5883 are probed but the drivers don't work as I have expected.
>>>> 
>>>> And I have updated the debian/lxde rootfs scripts [3] to better handle some dynamically changing /sysfs nodes (e.g. the tvout script and the hw-test script).
>>>> 
>>>> BR,
>>>> Nikolaus
>>>> 
>>>> [1]: https://github.com/goldelico/gta04-kernel/tree/3.12-wip
>>>> [2]: http://git.goldelico.com/?p=gta04-kernel.git;a=shortlog;h=refs/heads/3.12-wip
>>>> [3]: http://git.goldelico.com/?p=gta04-rootfs.git;a=summary
>>> 
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