Re: [Ksummit-discuss] [CORE TOPIC] Mainline kernel on a cellphone

[Bintian <bintian.wang@huawei.com>]

Hi All,

I am also very interested in this topic, and now I am focusing on
Huawei cellphone kernel development.

One month ago, I submitted the basic system and clock driver of HiKey
to linux kernel, and HiKey is the prototype of Huawei Honor 4X
cellphone.

We really hope people can download the latest kernel code and run well
on HiKey(or other mobile products) at some future date, and now we try
to submit the rest drivers to kernel maillist.

On 2015/7/29 6:09, Tim Bird wrote:
> On 07/23/2015 08:40 AM, Mark Brown wrote:
>> On Thu, Jul 23, 2015 at 08:42:51AM -0400, Steven Rostedt wrote:
>>
>>> Although is this something to be a core topic or a tech topic? Does
>>> this affect all subsystems, or just a set of drivers? Note, a core
>>> topic wont get as much time for discussion as a tech topic would.
>>
>> It's basically all subsystems that get impacted, at the minute I'd say
>> it's more a plan of action and process discussion than a technical one
>> though in the context of KS planning that's quite probably the same
>> thing.
>>
>>> Also, what is expected to be solved at KS?
>>
>> Tim Bird (Cced) has been running some sessions at other conferences
>> scoping the problem and discussing ways to move forward on this, another
>> similar session might be useful.
>
> As Mark says, I've been working on almost exactly this topic for several
> months now.  Last year I conducted a survey investigating obstacles
> that developers (mostly corporate product developers) have in mainlining.
> There are lots of non-technical issues that are worth working on (version
> gap, corporate incentives, training, etc.), but which are outside
> the scope of the kernel summit.
>
> There are also some technical areas where I think coordinated
> effort might be useful, to identify deficiencies and collaborate on
> progress.  These might be worth discussing at the summit.
>
> In March of this year, I analysed code from several shipping phones
> (representing a number of different SoCs, including both ARM and
> Intel-architecture CPUs), and found that most products have between
> 1.2 and 3 million lines of code out-of-tree.  We are still in progress of
> finding patterns of out-of-treeness, to inform decisions about technical
> projects going forward.
>
> There is now a wiki page at:
> See http://elinux.org/Kernel_areas_of_focus_for_mainlining
> In particular it has a table showing certain areas that tend to have
> a lot of out-of-tree code (e.g. most phones have between 80K to
> 100K of lines of wireless driver support out-of-mainline)
Very glad to see Huawei P6 is also in your investigation list :)

For HiKey, the original display driver is based on Framebuffer, but we
need to reconstruct this driver based on DRM framework when do the
upstream work, one lesson we learned here is trying to develop drivers
based on the requirements of current linux sub-system.

>
> IMHO it would be useful to discuss these areas, to see if there
> are technical reasons for these deficiencies, and work to resolve
> them.
Agree.

Thanks,

Bintian

>   -- Tim
>
> _______________________________________________
> Ksummit-discuss mailing list
> Ksummit-discuss@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/ksummit-discuss
>
> .
>