The Université libre de Bruxelles held the event on February 3rd and 4th, and the program was more prosperous than ever. FOSDEM is always considered the best IT conference and it is entirely volunteer driven. Linaro attended the event with eight talks (having submitted about a dozen): a record-breaking presence and acceptance ratio! Beer was constantly flowing at Fosdem, yet there is no indication that Belgian beer is much better this year to draw the attention of so many of the following Linaro open-source contributors.
Caleb Connolly presented U-Boot for modern Qualcomm phones, where they discussed how bootloaders are often one of the most significant pain points when booting upstream Linux on Qualcomm devices. Caleb points out how distros which aim to support Qualcomm devices currently have to handle 4 versions of the Android boot image header plus many additional quirks. In this talk, they give a brief introduction of EFI bootloader, how they work, and how U-Boot fits into the picture as a second-stage bootloader. Caleb covered the work they’ve been doing to improve Qualcomm support in upstream U-Boot and how folks can drastically lower the barrier of entry for distro support on Qualcomm phones. Lastly, they discussed the new process for porting a Qualcomm device and SoC to U-Boot and showcased a cool demo booting Linux with EFI runtime support on a Qualcomm phone.
Presentation Slides // Talk Video
Bryan O’Donoghue talked about a fully open-source stack for MIPI cameras. It was a joint talk with Bryan and Hans De Goede from Redhat about supporting MIPI cameras with a fully open libcamera / Linux kernel stack.
Linaro has engaged with libcamera to provide a Soft ISP solution for MIPI cameras. Several other organizations are interested in this solution - including Red Hat on both the ARM64 Laptop, x86 Laptop, and embedded IOT Arm side of things.
We discussed at a high level what the core problem to be solved is - debayering, 3As in the absence of Hard ISP support, how we engaged with libcamera on design and implementation, the state of the art in CPU ISP and near future extensions to GPU ISP.
Presentation Slides // Talk Video
Neil Armstrong discussed Mainline Linux on Qualcomm SoCs, are we here now? For the last ten years, Qualcomm’s engineers and Linaro’s Qualcomm Landing Team have been working hard to implement Linux mainline support for Qualcomm platforms carefully, and so far, so good as you can judge with the very good Thinkpad X13S support.
Neil did a tour of all supported platforms, describing the work Linaro’s Qualcomm Landing Team has achieved and the key features engineers are working on.
The Qualcomm SoCs are notoriously very complex and powerful, and implementing clean, correct, maintainable, and extensible support for mainline Linux is particularly hard.
Key domains like Power or DSP management were particularly hard to support, with those in good shape multimedia, connectivity, and network features getting enabled, permitting Qualcomm-based devices to offer excellent support while running vanilla (unmodified) Linux kernel!
The Thinkpad X13s is an excellent example of such support because, until recently, it was limited to expensive and hard-to-buy Qualcomm Reference platforms.
Nevertheless the Qualcomm Reference platforms get as early as possible mainline support, without any concessions on code quality, like the Snapdragon 8 Gen 3 mailing-list patches delivered on marketing announcement day.
The talk gave a tour of supported platforms, current and possible future achievements, and integration examples with mobile distributions like PostmarketOS.
Presentation Slides // Talk Video
Rémi Duraffort gave a talk about A simple caching service for your CI. Kisscache is a simple caching service developed by Linaro for the LKFT (Linux Kernel Functional Testing project at Linaro) to cache test artifacts like kernel, dtb, and root filesystem. While pretty simple, KissCache can cache https URLs without any hacks that proxies like squid will require.
Kisscache is intensively used at Linaro to reduce the amount of data downloaded by the CI system while improving reliability with automatic retries. Since its introduction two years ago, KissCache has been able to save 1TB of data transfer and decrease the number of network failures.
In this short introduction, I will show you the features that make this service so efficient for LKFT.
Presentation Slides // Talk Video
Rémi Duraffort’s second talk featured Ghosting the hardware. LAVA, the Linaro Automation Validation Architecture, is now the standard system for testing software (from bootloader to kernel or userspace) on both virtual and real hardware. It’s used by many projects to build large testing systems like kernelci or LKFT (Linux Kernel Function Testing project from Linaro).
To build a stable CI system, we have to ensure that LAVA itself does not regress from one version to another.
In this talk, Rémi presented how the LAVA team is intensively using mocking to test LAVA on devices that none of the team ever saw.
Presentation Slides // Talk Video
Thomas Fossati presented Increasing Trust and Preserving Privacy: Advancing Remote Attestation.
Thomas gave a talk in the confidential computing devroom about remote attestation. It was co-presented by Thomas and Ionut Mihalcea from Arm. Hannes Tschofenig was also a co-inspirator, but couldn’t attend the event. This talk was the last one on Sunday night, and we were pretty knackered by then, but it was fun. During the talk, we discussed the history of attestation, from its theoretical beginnings at PARC in the 1980s, through trusted computing to confidential computing, and finally, to its integration into network protocols. Attestation has moved from a niche technology to being widely available in laptops, servers, and IoT devices. We highlighted some of the technical and societal implications of using this technology. On the societal front, we discussed the risks associated with centralization (i.e., the opportunity of monopoly) and privacy concerns. On the technical front, we argued about the need to ensure that integrations of attestation into existing authentication protocols are done securely. Finally, we proposed a model for minimizing risks and maximizing utility based on open standards, open-source software, and formal verification
Presentation Slides // Talk Video
Dmitry Baryshkov discussed Using linux-yocto as a Yocto BSP kernel. The `linux-yocto` kernel is widely known as a default OpenEmbedded / Yocto kernel, used for QEMU machines and several default Yocto BSPs. For other platforms, it is used quite rarely. Nevertheless, it is a kernel recommended by the Yocto Project Compatible Layer program. This talk was dedicated to switching the Qualcomm Yocto BSP layer from the Linaro-backed kernel to linux-yocto. The talk provided a step-by-step guide and listed the positive and drawbacks of such conversion. Also it covered the peculiarities of the linux-yocto itself and its config system based on the features files and config snippets.
Presentation Slides // Talk video
William Breathitt Gray presented Synergy in Open Communities. William talked about synergy in open communities. Synergy is when multiple parties come together to produce something greater than the sum of their parts, and it’s what we will strive for in this talk. When an open community like an open source project grows, external contributions increase.
One of the primary benefits of open communities is the assimilation of progress from a broad and diverse pool of talent. However, care must be taken to ensure that the acceptance process is free from social friction, lest arguments bring down and delay the development of the project.
This lightning talk covers the social issues open community maintainers and external contributors face during the submission of a patch or other change, why conflicts arise between parties, and how to handle complex public disagreements to bring threads of discussions back on topic to focus on the benefit of the project and community.
Presentation Slides // Talk video
This is just a brief snippet of the talks by Linaro engineers. The slides and videos of these talks are also available. There were many more talks on a wide array of topics, folks are encouraged to look at the slides and videos. It was a pleasure attending the FOSDEM24 amidst the grey sky and long food queues, but the enthusiasm of participants and quality of the topics made it worthwhile.