On 4 April 2012 09:54, Chris Simmonds chris.simmonds@2net.co.uk wrote:
On 04/04/12 11:53, Amit Kucheria wrote:
On Wed, Apr 4, 2012 at 1:31 PM, Chris Simmonds chris.simmonds@2net.co.uk wrote:
Hello,
I am working on behalf of an SoC vendor and I am trying to work out which (if any) of the many git trees at http://git.linaro.org/gitweb we should
Is this a new SoC (no mainline support) or an existing SoC?
It's a new SoC which will have its own arch/arm/mach-xxx directory
Ideally I would like a "long term support" Linaro kernel. Since that doesn't exist, one approach is use the linux-linaro-tracking tree but only use the linux-linaro-3.0* tagged versions so that we can easily merge in changes from v3.0 from kernel.org linux-stable.
LTSI is something that is work in progress by the Linux Foundation. But that is directed towards products shipping with already enabled SoCs. I don't think it is a good tree to follow for new SoC enablement.
LTSI is interesting and something that I would like to track. But it does not help me with core arm support.
So my questions are
- Is this a rational approach?
IMHO, you should be developing against mainline, say the last released kernel 3.3, if tracking 3.4-rc is too much. And then ask for it to be merged via the arm-soc tree if you have no other sub-arch maintainer above you.
It is not feasible to track the tip mainline release both because it eats up man power in the kernel team but even more so in the QA team. Probably looking at one kernel release per year, ideally based on the long term kernel, currently 3.0.
When it comes to mainlining, is arm-soc the best way? There is no route via Linaro?
- Is this how you imagine other projects interfacing with Linaro? Or
should we really be waiting for Linaro code to be mainlined and pulling from kernel.org?
If you need specific features from the Linaro tree, you should use git branches to track the tree and cherry-pick the bits that you do need. Can you give examples of things that you do need from the Linaro tree?
Basically, everything in arch/arm/kernel, arch/arm/mm, etc. Right now the diff is mostly to do with device tree, which is interesting but not crucial. But the principle is that linux-linaro will have arm architecture support before mainline, no?
We used to track the stable release of the kernel but are moving to tracking Linus' -rc tree and staying in sync with tip while merging in features that may not quite be ready fo upstream. Due to this, the deltas will be continuously changing For example, many of the Device Tree changes will get merged upstream but we will bring in other changes such as the Android upstream cleanups that may still be queued for the next merge window.
Since we are now tracking -rc, I think it is OK to work against our tree for new SOCs, specially if you want to enable features that are not yet in mainline. At the same time, keep a topic branch around that has only changes against mainline to make it easier to get those upstream.
Thanks, ~Deepak