What is LTSI?
LTSI is an industry-wide project created and supported by Hitachi, LG Electronics, NEC, Panasonic, Qualcomm Atheros, Renesas Electronics Corporation, Samsung Electronics, Sony and Toshiba and hosted at The Linux Foundation to maintain a common Linux base for use in a variety of consumer electronics products. The project creates and maintains a long-term industry tree, which is expected to be stable in quality for the typical lifetime of a consumer electronics product, typically 2-3 years.
This new initiative is crucial because device makers are doing significant back-porting, bug testing and driver development on their own, which carries substantial cost in terms of time-to-market, as well as development and engineering effort to maintain those custom kernels. Through collaboration in this initiative, these CE vendors will reduce the duplication of effort currently prevalent in the consumer electronics industry.
The LTSI tree is expected to be a usable base for the majority of embedded systems, as well as the base for ecosystem players (e.g., semiconductor vendors, set-vendors, software component vendors, distributors, and system/application framework providers). The LTSI project will combine the innovative features in newer kernels needed by CE vendors with a stable kernel, while helping those vendors get their code upstream to benefit the entire Linux community. The goal is to reduce the number of private trees currently in use in the CE industry and encourage more collaboration and sharing of development resources.
Overview of LTSI
The LTSI project is an industry-wide collaborative activity to minimize fragmentation, and accelerate further innovation of Linux by incorporating fixes and innovations from embedded system engineers. The LTSI project consists of three major activities as follows.
- Continue to maintain the long-term stable tree on kernel.org.
- Create and maintain the LTS industry tree (LTSI tree) and an LTSI staging tree associated with it.
- Create and maintain an industry staging tree to evaluate and filter features from the LTSI tree, and promote them to upstream through the community’s staging tree.
A Common LTS Kernel Tree for the CE industry
The LTSI tree is an industry-managed tree based on the long term stable kernel tree, and will be published and maintained by the Consumer Electronics workgroup. This tree, based on long term releases, is expected to be used in products. It provides a supported version that will be supported throughout the life cycle of the product and it will include extras needed for specific product support such as backported drivers and features, and other vendor patches.
A new tree will be selected roughly once each year, and versions will be refreshed every year to maintains at most 2 versions in 2 years. Kernel 3.0 will be the initial kernel in this series. Each long-term kernel will receive updates for two years as part of the usual stable update process.
The LTSI staging tree will be maintained separately for development and stabilization of upcoming features in the LTSI tree.
LTSI Industry Staging Tree
In parallel, a staging tree will provide a testing ground for all interesting code to its inclusion in the industry tree. A QA team will devote itself to testing the code in the staging tree before submission to upstream.
Direct Contributions to Upstream
LTSI provides a mechanism to accelerate contributions from industry engineers to get their code upstream into the mainline kernel. The staging tree will hold all such patches while they are made suitable for inclusion into the mainline. This approach will enable contributions from CE industry to flow in a very organized way back to the upstream kernel. The LTSI project has tight linkage with the community’s long-term-stable tree maintainer to select a base version of Linux for wider use in the industry, and close communications with upstream maintainers to incorporate fixes and innovations from industry engineers.
Infrastructure for CE industry to Collaborate with Kernel Community
The project unifies the CE industry players around collaborating on the Linux kernel and working for gaining upstream acceptance for the contribution from CE players. That kind of collaboration requires a support infrastructure. As such the LTSI project offers both technical and non-technical support infrastructure:
- Project web site
- Source code repository system
- Bug tracking system
- Mailing lists
- IRC channel for live discussions
- Wiki for collaboration on documentation
- Project management to track activities, milestones, deliverables, etc.
- Tree maintainers to oversee the LTS trees
- System administrator to ensure IT support