So since I landed support for the Raspberry Pi 2 and 3 just in time for Fedora 25 Beta it’s been a bit of a fun ride. The support for Raspberry Pi is mostly done in my spare time along side all the other responsibilities I have and it’s been interesting to see people’s feedback. Going into Fedora 25 I knew it wasn’t going to be perfect but the experience was going to be reasonable for newbies to get going without generally needing serial consoles and it met Fedora’s (and mine) exacting standards on free drivers. I think we achieved that quite well but I also learned a lot in the Fedora 25 cycle and what’s coming in Fedora 26 is quite a substantial jump forward.
Hardware for a good experience
So what have I learned about the first six months or so of Raspberry Pi in Fedora? Well there’s a couple of things that the user can do to ensure a decent starting experience themselves. The biggest FAQs I’ve dealt with on the various support forums are generally fixed by these three things:
- A proper spec power supply. For the RPi2 this means at least 2 AMPs and for the RPi3 at least 2.5 AMPs. If you want to plug in USB WiFi dongle and a USB HDD you’ll likely want to add a little more! In most cases an old phone charger will not suffice.
- A good quality Class 10 micro SD card. I generally use Samsung EVO or SanDisk Ultra cards.
- A Raspberry Pi 2 or 3. Yes, it’s surprising how many people hope to run it on something else. SORRY (actually, I’m not!)!
What’s in Fedora 26 Final
So enough of what to do! Everyone wants to know what improvements arrived in the Fedora 26 Final with the 4.11.x kernels:
- Pi3 WiFi: It’s been working in F-26 since Alpha and is surprisingly stable. There’s a file you need to grab to enable it. See details in the wiki here.
- Performance: In the process of dealing with wifi I worked out one of the reasons we were seeing poor performance on the SD card. We’ve had some minor improvements in F-25 but this fix over doubles the performance for me on the SD card.
- HDMI video: There’s been issues around certain monitors crashing the video (vc4) driver and people getting black screens during boot. While this isn’t perfect yet (ain’t hardware great!!) it’s greatly improved across numerous devices.
- Composite video: We’ve had support for the composite video since 4.10 but I need people to help test this.
- Sound: HDMI audio is supported, I’ve done minor testing with the one HDMI audio capable device I have. Analogue audio out isn’t upstream yet.
- HAT support: We now have all the support needed to do overlays in the kernel/bootloader and dtc stack. I just need to test it some more, document it and work out how we can best distribute pre built overlays to ease consumption. There’s still no consensus on an Overlay Manager from upstream to auto load overlays based on EEPROM on the HATs. In a lot of cases you want to load the overlays from u-boot anyway for things like display. Look out for docs and blog posts on this soon!
What arrived with the 4.12 kernel rebase
- Thermal support: so if the RPi runs too hot it’ll slow it down
- More performance improvements and tweaks.
What’s coming in the 4.13 kernel rebase
- Bluetooth support: upstream finally tracked down the issues here. It’s been a much requested features and I should have the bits in place soon!
- More performance, stability and graphics improvements and tweaks.
What about Fedora 25?
Some of the above pieces will be coming to Fedora 25 with the 4.12 rebase. The focus of my spare time is Fedora 27 mostly now, with the above coming to F-26. Some components are a lot harder to back port without issues or a complex series of package updates to ensure smooth upgrade. The WiFi and performance improvements were the hardest as part of that change moves around the use of hardware blocks and drivers. I managed to stop both the RPi2 and RPi3 booting numerous times in testing before I properly realised the implications of the change. Getting these changes for users back into a stable release without issues is hard and time consuming to do across all the various use cases. I tried this with some fixes in 4.9 and ended up making the RPi3 very unstable. This cost me a lot of time to debug and fix and I don’t really want a repeat of that!!
One of the surprising side effects was the discovery of a device that is five years old is that Fedora suffered from early adopters issues. We were one of the first distributions to adopt a fully upstream open kernel and graphics stack and with that came a number of issues around monitor detection, especially older/cheaper models that aren’t 1920/1080 “Full HD” or via HDMI to VGA adapters. We’re still working through these with upstream and have improved the situation quite a bit in Fedora 26 overall but it takes time and reproducible use cases which with random hardware isn’t easy or quick! 🙁
I’ll leave Fedora 27 features and functionality for another, this post has been sitting in my drafts folder since June so it’s time to get it out and like my development move on to Fedora 27!
The upstream Raspberry Pi firmware/bootloader gets regular updates and improvements. In Fedora we ship that firmware in a package called bcm283x-firmware. I regularly follow the git repo of the upstream firmware and on occasion when I believe there’s reasonable changes that benefit Fedora I’ll prepare a new version, do some brief testing on my devices to make sure it boots and basic functionality hasn’t regressed at which point I’ll update the package and send it out to supported releases as an update.
Once the new bcm283x-firmware lands on your Raspberry Pi it doesn’t automatically update the firmware though. Why is that you ask? I don’t like to spring surprises on people where they end up with a device that might not boot or it might regress things they care about.
So how do you upgrade the firmware for the Raspberry Pi on Fedora? It’s simple! You simply run the command rpi-firmware-update and it’ll update the firmware and the u-boot to the latest one that’s shipped as a Fedora package. Then you just need to reboot to make it active.
The easiest way to work out which firmware you’re currently running is “dmesg | grep raspberrypi-firmware”
I tend to try and push out a new firmware update every month or so but if I see something that’s of interest or that fixes known issues I do it as needed.
So a number of people have been discussing the Internet of Things on Fedora for some time. We now have a Fedora IoT mailing list where these discussions can be more centralised and directed.
So where and how do we get started here? I’m going to kick start some ideas here and repost it as a mail to the list so we can use it as a basis to start the discussion.
As I outlined in my Using Fedora as a base for the IoT revolution talk at Flock there’s a lot of use cases and components that make up a complete IoT stack. I think initially we should focus on two initial goals rather than biting off too much:
- A IoT internet gateway device
- A IoT sensors endpoint device
The general idea here is that both of the above would be a very minimal shared build, likely using atomic images to enable easy update/rollback with some specific components for each use case. Initially I suggest we focus on a single, or maybe a couple, of specific devices to limit the scope to something more achievable and to add features as we go.
IoT internet gateway device specs and features
- Wired and/or wireless ethernet to provide internet connectivity
- Bluetooth Smart (AKA LE)
- Thread Stack support (6LoWPAN and friends)
- 802.15.4 support
- MQTT Broker support (not standard for a IoT GW but enables easier localised testing)
- MQTT Client
- Atomic support: updates, rollback etc
- Works with both our endpoint below and other IoT OSes such as Contiki
IoT internet sensors endpoint specs and features
- Wired or wireless ethernet IP support
- Bluetooth Smart (AKA LE)
- Equivalent to Thread Stack support (6LoWPAN and friends)
- MQTT Broker support (not standard for a IoT GW but enables easier testing
- MQTT Client
- CoAP client
- Atomic support: updates, rollback etc
- Support for various inputs and outputs and sensors
I have no doubt missed a lot of details in the above use cases, it’s somewhere to start. I think we also need to look at tools like Node-RED and tools for managing the devices. IoT is a big topic, the idea is we need to get the conversation start somewhere. I’ll look forward to seeing you all on the list to do that.
I’m not going to do a day by day outline of what I did at flock, if I did it would basically be “blah blah blah I talked a lot to a lot of people about a lot of tech topics” and anyone that’s ever met me would have guessed that! It was, as in the past, a great conference. A big shout out to the organisers for an excellent event with two excellent evening events! So I’m going to give a brief summary to my talks and link to slides and video recordings.
My first talk was an overview of the state of aarch64 and POWER as secondary architectures. The slides aren’t particularly interesting as they’re just words for discussion points. The video has all the interesting bits. A related talk was Dennis’s Standardising ARMv7 booting with a memorial quote by Jon Masters 😉
My second talk was about using Fedora as a base for IoT. Slides are here but the talk was quite a bit different to the slides and is more interesting so I suggest watching the video.
I also actively participated in Dennis’s Fedora Release Engineering going forward because well obviously I’m part of it 😉 and it was interesting for where we’re going, and even where we’ve come from in the last year or so 🙂
Finally I loved the Keynote Be an inspiration, not an impostor by Major Hayden. He’s published a follow up blog post with a FAQ too.
The least memorable bit was the terrible Amtrak ride back to New York City. On the plus side it makes the worst of the British National Rail service seem amazingly on time! NEVER AGAIN!
I’ve been a bit lazy on the ARM kernel status updates. There wasn’t one at all for 3.18 but the fact was, that while there was lots of under the hood improvements for ARM/aarch64, the new device support or improvements from a user’s point of view was positively boring so I never bothered!
That said the 3.19 kernel is now on it’s way to the stable Fedora releases and there’s some bit of interest there 🙂
Beginning with aarch64 there’s been a raft of code support landing upstream for the core platforms we support (VExpress, APM Storm, and AMD Seattle) which means the enablement patch set has shrunk massively. The core missing bit from this is primarily the ACPI patches for the server standards. There’s also been a lot of stability improvements for various device drivers particularly on the APM Storm SoC (which massively helps the high network and IO traffic we generate when doing composes in release engineering!). Other improvements include support for seccomp. The upstream support for aarch64 is really starting to settle down nicely which is good because there’s devices finally starting to get to the point where they’ll be more widely available and affordable 🙂
On to ARMv7 changes. In terms of new supported SoCs the support for AllWinner A-23 (aka sun8i) is the most interesting in terms of new devices. There was also a lot of general SoC improvements and cleanups. The largest here is probably Rockchips, QCom and ZYNQ with notable mentions to Tegra, OMAP and i.MX6 too. In terms of new devices we now solely support DeviceTree devices and the built .dtb files we ship that are possible to support with the kernel jumped from 250 to 265 devices. Of course it doesn’t mean we’re testing all of those devices but we’re testing devices across all main SoC groups to ensure at least the core support works. Of course feedback for what works and doesn’t is always welcome. In this cycle there was also significant driver work with special mention to Hans and his significant movement on the Allwinner devices.
I’ll do a longer post for 4.0 and the new u-boot we’ll be supporting in Fedora 22 soon.
A question that I’ve had a few times in the last couple of weeks is whether Fedora supports Cute Embedded Nonsense Hacks, also known as u-boot and device tree, on aarch64 (ARM64) platforms?
The answer is YES!, of course, why wouldn’t we?
I know people are well aware of Red Hat’s involvement in the Server Base System Architecture (SBSA) which mandates the use of UEFI 2.4 and ACPI 5.1 bindings and that the Red Hat Partner Early Access Program uses that standard to enable easy booting and support of server platforms running on aarch64 platforms but the fact is that is not Fedora.
Fedora plans to support the SBSA to enable easy use of Fedora on aarch64 server platforms. But we also plan to support the current standard u-boot with device tree boot options. The fact of the matter is that a lot of non server based aarch64 platforms will continue to use these options and so we’ll continue to actively support them. Just like Fedora support Xen when the Fedora derived enterprise product does not. Basically it’s not hard for us to continue these options and with the improved generic distro support in u-boot, which we’ve actively participated in and driven, testing of Cute Embedded Nonsense Hacks on aarch64 should be easy and straight forward.
Of course the support of both SBSA based uEFI/ACPI or u-boot/DTB isn’t perfect on aarch64 yet so if you’ve got access to aarch64 systems on either platforms I would love testing and bug reports. If you’re a vendor that plans on using u-boot/DTB on aarch64 I would ask to ensure that you support the generic distro options because it’ll enable out of the box booting of at least Fedora, Debian and openSUSE to seamlessly just work on your devices.
With 3.17 due momentarily and Fedora 21 been delayed a little we’ll now be bumping the kernel that ships in F-21 GA. So lets have an overview of what improvements and changes are going to be there for ARM.
Overall 3.17 has been relatively boring in terms of shiny new hardware support for ARMv7. We’ve added support for a bunch of new devices through the addition of appropriate device tree bits. Some of the highlights there include a number of AllWinner devices such as the Banana Pi, a number of new FreeScale i.MX6 devices, some of RockChips devices, and the ZYNQ Parallella.
On the aarch64 side there’s been general improvements all over the place. Over all we don’t have any new platforms but there’s improvements to the three we do support (VExprees, APM X-Gene, AMD Seattle) but the VExpress Juno device should work and initial support for the ACPI 5.1 standard and improved uEFI both of which are part of ARM SBSA Server standard.
Along side 3.17, or at least very shortly there after, u-boot 2014.10 or at least a release candidate should land in F-21 as well. This release adds support for a lot of new devices, primarily AllWinner A-10/13/20 categories, as well as the Tegra Jetson K1, a few i.MX6 devices such as the RIoT Board and the newly upstream distro standards for booting. This makes it much easier for us to “just boot” Fedora ARM with a lot more devices making the experience of getting started a lot easier for most people with supported devices.
The combination of u-boot 2014.10 and the 3.17 kernel will be what we head towards Fedora 21 GA with and things are starting to come together nicely.