Embedded Flag Version Recently, two embedded Linux summit meetings were held, one in Tokyo, Japan and one in Cambridge, UK. The purpose of these meetings was to discuss among industry and community leaders things that might help improve the value or decrease the cost of embedded Linux. One initiative which came out of these meetings, was the notion of declaring a "flag version" of Linux, for embedded use. This would be a specific version of the Linux kernel, chosen as a rallying point for embedded Linux software, add-ons and products. In hearing from several different consumer electronics product companies and semi-conductor producers at the summits, it became apparent that a significant problem in the embedded space is variation in the kernel version. This could be called version fragmentation. Companies, especially those at the end of the software supply chain, often get stuck using a particular kernel version for a product due to the cost to integrate software coming from different entities. Of course the optimal solution to this problem would be if all required software were pre-integrated into the latest stable release, at all times. However, software can not be mainlined instantaneously. Not everyone is using the latest version of the Linux kernel (2.6.36, as of this writing). In point of fact, no one in the CE industry does (or really can), use the absolute latest kernel for a product that is shipping today. It takes time to assemble the software and perform the testing required to ship a product. However, it is desirable for many reasons to stay as close to the current version of Linux as possible. Selecting a "flag version" is intended to help with this problem. First, it should be explained what having a flag version means. It means that suppliers and vendors throughout the embedded industry will be encouraged to use a particular version of the kernel for software development, integration and testing. Also, industry and community developers agree to work together to maintain a long-term stable branch of the flag version of the kernel (until the next flag version is declared), in an effort to share costs and improve stability and quality. It may seem counter-intuitive that selecting a version of the kernel for long-term stable maintenance would help companies keep up with the mainline version. But there are a number of reasons why it can. First and foremost, a lot of effort is spent integrating software components to make a product. This includes software components from IP block vendors, semi-conductor vendors, parts suppliers, Linux vendors, and in-house software teams. By decreasing the effort required to integrate this software, it becomes possible to spend more time working on other features, and working with upstream, and increases the frequency that a company can afford to switch kernel versions. Also, by leveraging the testing of multiple organizations and developers, including those outside one's own company, a group can more quickly ensure that a kernel is suitable for production use. This also decreases the effort required to use the kernel, and increases the possibility of quicker version changes. It was noted at the summit that several CE companies and embedded projects will be using (or are already using) 2.6.35 for upcoming products or releases. This includes Sony, Google, Meego, and Linaro. On behalf of the CE Linux Forum and a number of consumer electronics companies, projects and community developers, we therefore declare 2.6.35 as a flag version of the kernel for embedded use. Several companies will be investing in development, integration and testing of this version. Entities wanting to do business with those companies would therefore be well-advised to make sure their hardware, drivers and enhancements work well with this version of the kernel. Tim Bird Architecture Group Chair CE Linux Forum November 4, 2010 -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
