Using fwupdmgr to update NVME firmware

The fabulous fwupdmgr provides the ability to easily update firmware that is published to Linux Vendor Firmware Service (LVFS) but it can also be used to apply updates that aren’t necessarily in LVFS. One type of firmware that it supports updating is NVME firmware, that’s basically any NMVE, because the standard specifies a standardised mechanism for updating the firmware on all NVME devices.

I had a need to update a NVME firmware in an aarch64 device to see if it fixed an issue I was seeing. The Crucial P2 supported options were of course x86 only. The ISO download actually contained a little LinuxOS in an initrd on the .iso. The advice from Richard the fwupd technical lead was to “Look for a ~4mb high entropy blob” so mounting it up, I mounted the iso, extracted the initrd, and then used fwupdmmgr to apply the new firmware.

Find the NVME and check the firmware version:

$ cat /sys/class/nvme/nvme0/firmware_rev 
P2CR010 

So once I’d downloaded the update file I did the following to extract and update the firmware. Note I did this all as root, you can do most of it as non root.

# unzip iso_p2cr012.zip
# mount -o loop iso_p2cr012.iso /mnt/
# mkdir ~/tmp
# cp /mnt/boot/corepure64.gz tmp/
# cd tmp
# gunzip corepure64.gz
# cpio -iv < corepure64
# fwupdtool install-blob opt/firmware/P2CR012/1.bin
Loading…                 [-                                      ]
Loading…                 [-                                      ]
Choose a device:
0.	Cancel
1.	71b677ca0f1bc2c5b804fa1d59e52064ce589293 (CT250P2SSD8)
2.	2270d251f7c1dc37a29a2aa720a566aa0fa0ecde (spi1.0)
1
Waiting…                 [************************************** ] Less than one minute remaining…
An update requires a reboot to complete. Restart now? [y|N]: y

And away it goes, a reboot later and did it work?

$ cat /sys/class/nvme/nvme0/firmware_rev 
P2CR012

YES!!

Short history of ARMv7/armhfp/arm32 in Fedora

Back in mid November I proposed a change for Fedora 37 to retire ARMv7 as an architecture, FESCo accepted the proposal. Per the Fedora 36 schedule we branched Fedora 36 this week. Last night I enacted the last of the process to disable it in rawhide so to quote “It’s dead Jim”. The last release of Fedora to support ARMv7 AKA armhfp AKA arm32 will be Fedora 36 which will go end of life around June 2023.

I thought I’d cover a few of the things we achieved with Fedora ARM and some of the impact it’s had on the wider Linux on ARM ecosystem which people may not have realised.

First a little bit of ARM history in the Fedora ecosystem. The beginnings of ARM support actually precedes Fedora all the way back to 1998 with a fork of Red Hat Linux 4.2 and more officially with Red Hat Linux 5.1 on the Corel Netwinder (I always wanted one of those but they weren’t available in Aus).

In Fedora itself the earliest details I remember was that Marvell bootstrapped ARMv5 in Fedora 7 and continued to build and support it through to Fedora 12. This “software architecture” was known as softfp. It was optimised for the ARMv5 architecture which didn’t have a hard requirement on a floating point unit so emulated it when it was needed hence “software floating point”. In Fedora 13 Seneca College took over the ARMv5 infrastructure and building from Marvell. I officially got involved in the Fedora 14 build process and soon after was also contracted by OLPC to drive Fedora on OLPC for their ARM based XO laptops as well as work on their i686 devices to have a single OS for all of them.

In mid 2011, the Fedora 15 timeframe, a small Red Hat team started to do a ARMv7 hard floating point, AKA hardfp or armhfp, bootstrap as ARM’s new v7 mandated a floating point unit. The bootstrap included the core toolchain (binutils/gcc/glibc/elfutils and friends) and ultimately the entire distribution, I drove this effort from a community, build and packaging perspective. This required 100s of patches to upstream projects that made many assumptions about ARM only being softfp, but it also allowed us at the time to fix many general architecture assumptions in these projects. The hard floating point bootstrapping was useful for the wider community too, it was used by Nokia as the base of it’s hardfp efforts for Maemo, plus other distros used it as as it’s much easier/quicker if you already have a full distro running the architecture you wish to boostrap. What wasn’t generally known at the time was also the first new architecture that has been bootstrapped in the Fedora/RHEL ecosystem since x86_64 a long time before and it allowed Red Hat to refresh it’s memory on how to do this in preparation of the then unannounced aarch64 architecture and the POWER Little Endian intentions, basically it provided a cover story. We also worked to get other languages such as Fortran, golang, rust and others building and working on armhfp and those other architectures. The final piece of this was ARMv7 being promoted to a primary Fedora architecture in Fedora 20. This then later went on to my proposal to redefine secondary architectures in Fedora.

In the wider community of Linux Fedora ARM was the first distribution to adopt the kernel “multi platform” work enabling us to go from building 5 different kernels to support a handful of arm devices to a single kernel supporting 100s of devices in a very short period of time. I worked with closely Arnd Bergmann from Linaro on issues with the early pieces of the multiplatform work. In upstream U-Boot we posted the first distro_boot patches to support booting Linux in the same way across all the devices we actively supported so we didn’t need specially wrapped kernels and know exact offsets for every SoC or device. The distro_boot support evolved, working with SUSE, into UEFI support in U-Boot further standardising the ARM boot process by abstracting the pieces that were different and letting the firmware deal with them. This work ultimately evolved into EBBR and the ARM System Ready IR spec. In Fedora 34 we moved to soley supporting UEFI on both ARM architectures. A lot of Linux distros still have specific kernels for each device and use non standard boot methods for devices and hence have an image for each device/use-case they wish to use. This was something Fedora identified very early on as something that would not scale!

Fedora also leads a lot of things in the gcc toolchain stack across all our supported architectures, we’ve actively enabled a lot of security features and other things like LTO early on. As the Fedora gcc maintainers, employed by Red Hat, are also key upstream GCC maintainers we’re almost always the first distribution to rebase onto a new release before it’s a stable release, for example Fedora 36 had just had a mass rebuild against a gcc-12 pre release snapshot. This builds all of the 50k or more source packages with the pre-release of the new toolchain making for a much better release for the wider GCC community because this picks up a number of bugs/regressions in both the general support but also in the architectures Fedora supports which means the ARMv7 hardfp support in GCC has benefited from 100s of bugs we’ve detected in gcc/binutils/glibc etc before they land in a stable gcc release. With the retirement of ARMv7 in Fedora this is going to be something the wider ARMv7 community is going to have to pick up post the GCC-12 release.

Over the subsequent 11 years of ARMv7 support in Fedora, and much longer if you include the early ARMv5 the distribution has also enabled a number of other innovative features like support for containers, support for devices like the Raspberry Pi 2 and 3 in Fedora 25. as mentioned various toolchains, and fun things like robots. Of course we also lose some things too. Devices like the BeagleBone don’t yet have a 64 bit sibling, but there’s less and less 32 bit devices coming out and the use of armhfp is waning quickly and the maintenance cost is rising as the industry moves more generally to 64 bit even in embedded use cases and the fact is with devices like the $15 Raspberry Pi Zero 2W it makes less and less sense even if I do still actively run BeagleBones, a Panda-ES and 3 different i.MX6 devices.

So I engaged with the wider Arm ecosystem and it made sense to finally sunset our ARMv7 32 bit support. We’re of course leaving it in good shape with things like gcc-12, the latest rust and golang toolchains and 5.17 kernels, much newer by the time F-36 goes EOL in June 2023, it will be in good shape if people wish to use it as the basis of some form of continuing ARMv7 supported Linux distribution.

Sail off into the sunset friend, it’s been a fun 12 years of hacking on those projects!

Fedora on NVIDIA Jetson Xavier

The last two years or so I’ve been working with NVIDIA on general distro support including UEFI and ACPI for their Jetson Xavier platforms. Their Xavier platform, except a few quirks, are mostly SystemReady-ES compliant, so having a SBBR compliant firmware goes quite some way to having a widely available, relatively affordable, platform that “just works” for the arm ecosystem. I was very excited to finally have NVIDIA finally release the first version in March this year. This firmware is a standard UEFI firmware based on the open source TianoCore/EDK2 reference firmware, it allows booting in either ACPI or Device-Tree mode and supports all the basic things needed. The ACPI mode is not as fully featured as the Device-Tree mode as yet. In ACPI you get compute (cpu/memory/virt etc), PCIe, USB, network, which is just fine if you’re just looking for standard server or for testing a SystemReady system but there’s no display or accelerator support as yet. The Device-Tree mode is more feature full but both work pretty well with upstream kernels and NVIDIA are improving and upstreaming more things regularly.

For flashing with the latest Fedora releases you’ll want the Linux for Tegra (L4T) R32.6.1 release and the latest UEFI firmware (1.1.2 ATM). The R32.6.1 release fixes issues with python3.9 and later so you’ll need that for Fedora. The following will extract everything into a directory called Linux_for_Tegra. Note the release for Xavier is different to the L4T for the TX1/TX2 series of devices such as the nano.

$ tar xvf Jetson_Linux_R32.6.1_aarch64.tbz2
$ tar xvf nvidia-l4t-jetson-uefi-R32.6.1-20211119125725.tbz2
$ cd Linux_for_Tegra

To flash either the Xavier AGX or NX you need to put them into recovery mode and connect a USB cable, USB-C for AGX or micro-USB for NX. Once you’re in recovery mode you can flash them.

For the Xavier AGX:

$ lsusb | grep -i NV
Bus 001 Device 086: ID 0955:7019 NVIDIA Corp. APX
$ sudo ./flash.sh jetson-xavier-uefi-min external

For the Xavier NX:

$ lsusb | grep -i NV
Bus 001 Device 089: ID 0955:7e19 NVIDIA Corp. APX
$ sudo ./flash.sh jetson-xavier-nx-uefi-acpi internal

There will be a bunch of output and it will eventually return to the prompt and reset the device. You can now install Fedora on the device. You can use any of the pre-canned aarch64 image or traditional installer available from the fedora website. When running in ACPI mode you don’t get display output so you’ll need to use a serial console, in both ACPI and Device-Tree mode there’s not currently support for accelerated GPU graphics/AI/ML support. If you want to be able to easily switch between ACPI/Device-Tree modes you’ll want to install the dracut-config-generic package to have a generic initrd to make it easy to reboot between both modes.

SystemReady ES support for MacchiatoBin

I’ve had a MacchiatoBin Double Shot board for some time. It runs various services for my local network and generally just works. I run a TianoCore EDK2 firmware on it using ACPI. It’s purely a network device so I don’t bother with any form of graphics and in the very few occasions I need to access it locally I do so via the built in USB serial TTL.

Recently Solid Run announced the MacciatoBin is now SystemReady ES certified. Excellent news! I’ve worked with Arm for some time on both the SytemReady ES (Embedded Server) and SystemReady IR (IoT Ready) standards and recently the certification program has been finalised so it’s nice to start to see the fruits from all the hard work myself, and may others, have done over a number of years appear.

The EDK2 firmware I was running was coming up to two years old and there’s been a number of enhancements to the various components of the firmwares that make up a complete update so I decided to download the latest firmware and update it. Eventually I am sure Solid Run will have these published to LVFS to make the process even easier but I know that to get to this stage has been a LOT of effort so it’s still a great step forward.

The first step of updating a EDK2 firmware is to download it and put it on the EFI partition:

peter@macbin:~ $ wget https://github.com/Semihalf/edk2-platforms/wiki/releases/flash-image-a8k-mcbin.bin_r20210630
peter@macbin:~ $ sudo mv flash-image-a8k-mcbin.bin_r20210630 /boot/efi
peter@macbin:~ $ sudo reboot

On reboot you’re given a prompt to interrupt the boot process. From the menu select the option for the shell:

Shell> fs0:
FS0:\> ls
Directory of: FS0:\
04/06/2021  19:08          4,096  EFI
07/25/2021  17:01           2,855,040  flash-image-a8k-mcbin.bin_r20210630
          1 File(s)   2,855,040 bytes
          1 Dir(s)

FS0:\> fupdate flash-image-a8k-mcbin.bin_r20210630
Detected w25q32bv SPI NOR flash with page size 256 B, erase size 4 KB, total 4 MB
Updating, 99%
fupdate: Update 2855040 bytes at offset 0x0 succeeded!
FS0:\> reset

It then reboots and we’re done, you see a very similar output to previously with some updated versions of various firmware and before long you’re back through grub and running Fedora again. Painless!

I’m really happy to see this is such a straightforward process, and I’m looking forward to seeing more features, enhancements and fixes to the firmware including capsule updates and the associated LVFS/fwupdmgr support, and improvements around firmware security (fwupdmgr –force security). Top marks to the Solid Run team!

Setting the wireless regulatory domain

Different regions around the world use slightly different frequencies for the various wireless interfaces available on your average Linux portable device such as WiFi, Bluetooth and other such interfaces. Overall they fit into larger categories such as 2.4Ghz, 5Ghz etc, but within each of these larger buckets countries have a subset of the frequencies, generally referred to as channels available. For example the 2.4Ghz range used by most WiFi and Bluetooth interfaces has potentially up to 14 channels available, the default is a generic “world” region which uses 11 channels that are available in all regions, but a lot of regions have 13 available for use, and some even have 14. The situation is similar on the 5Ghz range, and no doubt on the higher frequencies now becoming available too.

So to make best use of these while operating in the legal ranges for a country the regulatory domain needs to be set for the device. Linux handles this with three components, the kernel CRDA interface, a signed regulatory DB, which in Fedora is a package called wireless-regdb, but may also be called crda, and the iw tool. In some cases if an access point is using channels outside of the default “world” range you may not even be able to see/connect to the network.

There’s a two ways you can fix this. Firstly straight on the command line with the following command line options. The first shows you the current settings, the next sets the domain for the UK, but setting it this way isn’t persistent, but it’s useful for testing:

iw reg get
iw reg set GB

To make the setting persistent on every boot you just need to set a country in the /etc/sysconfig/regdomain file with a line that looks like this:

COUNTRY=GB

Of course use the code for your country of location based on the standard two letter country codes.

Documenting my various arm and IoT devices: quick overview

It’s been around ten years since I got my first arm single board computer, a Beagle-xM, which started me down the route of playing with Fedora on ARM and ultimately to my role in device edge/IoT at Red Hat. Shortly after that time I also moved into my current flat, almost ten years later I finally made the decision to move to a new place.

In the process of unpacking the contents of boxes from the flat into my new home office I thought I would document all my devices. This is mostly for my own reference, but I have little doubt others are interested from previous conversations. I’ve broken the list down into a few broad categories, mostly so the blog post isn’t unwieldy, there’s certainly cross overs between the categories, like some generations of the Raspberry Pi can run in either 32 or 64 bit mode, some Arm SBCs also have an integrated micro controller etc. For simplicity I’m putting those cross over devices in a single list, that of which they’re most capable, I’m also not putting devices on the list that aren’t easily able to run an open source OS such as Linux or Zephyr RTOS as I have numerous micro controllers/phones etc I can’t be bothered with and hence they’re not seen as useful for this list.

The lists, I will update with links as I post them, are going to be as follows:

  • Part one: Arm 64 bit devices (aarch64)
  • Part two: Arm 32 bit devices (ARMv7)
  • Part three: Micro controllers
  • Part four: x86 and other devices

Three ways to speed up dnf on arm devices

I have a large bunch of Arm Single Board Computers I use for testing a lot. Most of the testing ends up being pretty basic stuff like firmware, kernels, and the various bits of hardware peripherals that people use like storage, network, display and sound output, plus things like sensors and HAT support.

The problem is that these devices often aren’t the fastest in the world for various reasons so I want to be able to apply updates to the basic system as quickly as possible to find out the results. Over time I’ve worked out that these three things speed up dnf quite a bit for the sort of testing I wish to do are as follows:

  1. Disable modularity:
    sed -i 's/enabled=1/enabled=0/' /etc/yum.repos.d/fe*mod*
  2. Don’t install weak dependencies:
    echo "install_weak_deps=False" >> /etc/dnf/dnf.conf
  3. Disable dnf makecache. It never seems to be up to date when you need it anyway:
    systemctl disable dnf-makecache; systemctl mask dnf-makecache

You may need to re-do some of these each major update as they seem to want to force you to have them every time.

Thoughts on Project Connected Home over IP (CHIP)

In late December 2019 Google, Amazon, Apple and a number of other companies announced Project Connected Home over IP. Like all Internet of Things I thought I would dig into it and see what it’s made up of.

First thoughts before I even began to dig were basically “well they got there eventually!” as I’ve long believed that for IoT in the home to be successful as a whole there needs to be a single set of open standards that all devices speak so that the things can intercommunicate…. you know, just like the internet! But like so many of these things the big companies always attempt to see if they can control the entire market first, then realise they need to “compromise” and work with the other players on standards, which is when the market starts to actually mature and consumers start to win out!

If you look at the project’s web site there’s, at least at the time of writing, 16 company logos on the page, of which around six or seven I would consider household names. A standard such as this was always going to happen. If you look at the “Home IoT Market” it’s a mish-mash of competing and incompatible standards, none of which really have a lead and some of the big names, such as Apple with their HomeKit interface (I refuse to use the term “standard”), have been struggling to get any real level of foot hold in the market. Some of the more popular off the shelf devices have been things like Samsung’s “SmartThings” which implement a number of different radios etc as bridge/gateway devices to make other things work together, which in and of itself speaks volumes. If the companies themselves didn’t get themselves sorted out it would have ended up in governments mandating something. In short the whole category is a big mess!

So reading through the FAQ and various bits in the media about it what does it appear to do? It puts IP over stuff! Shocking right!? To quote the FAQ:

The goal of the first specification release will be Wi-Fi, up to and including 802.11ax (aka Wi-Fi 6), that is 802.11a/b/g/n/ac/ax; Thread over 802.15.4-2006 at 2.4 GHz; and IP implementations for Bluetooth Low Energy, versions 4.1, 4.2, and 5.0 for the network and physical wireless protocols.

So the technologies they’re using are WiFi, no real shock there, although there’s no mention of Wi-Fi HaLow AKA 802.11ah but for home use that’s nothing of note. Next up in Bluetooth LE, 4.1 – 5.0, again no real surprises here, there’s already a standard for IP over Bluetooth LE/mesh in the form of 6LoWPAN, the same as used by Thread and vanilla 802.15.4, slightly interesting they mentioned explicitly 3 versions of BT-LE and just didn’t say BT-LE in general as all versions support IP. The final option mentioned was 802.15.4, the bit that I find particularly interesting here is that Zigbee Alliance was one of the four companies in the original announcement, 802.15.4 is an open radio standard used by Zigbee, Thread, 6LoWPAN directly and a number of other protocols, Zigbee has their own Zigbee IP standard, which competes with Thread and others yet Thread, originally out of Google/Nest is the chosen one. I’ve also found Thread to not really be a completely open standard like TCP/IP, as while there is the OpenThread implementation, you need to be a paying member of the Thread Group organisation to have it certified!

So what else does the project offer? They mention the following but note the term “may include”.:

This may include a proposed standard for lifecycle events such as provisioning/onboarding, removal, error recovery, and software update.

I feel that the lifecycle events they mention are actually extremely important here, and standards in this area are just as important as connectivity standards such as IP for layer 3. If you look at components such as provisioning/onboarding there’s fairly new standards evolving such as the Intel/Arm FIDO secure device onboarding collaboration which are still quite new so I suspect they’re going to wait and watch these before making a decision which is actively a good thing in my opinion if it means one less new standard!

Overall there’s currently nothing actually new on offer here in terms of standards, what is new is a number of large companies committing to focusing on a single Layer 3 connectivity protocol. There’s already widely available hardware across WiFi/Bluetooth/802.15.4 as well as standard IP implementations for them all. This should actively replace Zigbee, Z-Wave and a number of other proprietary Layer 2/3 protocols and should be straight forward for adoption as there’s not actually a lot for anyone else to do.

I feel this is a move in the right direction and will make life easier for a lot of third parties who want their products to work with “the big three of Apple/Google/Amazon”, the move to more open standards is obviously good, but overall there’s really nothing particularly new other than another mechanism for closed companies to work together. I don’t think it’ll ultimately make much difference in general to the open source community as those companies will have their proprietary protocols/APIs sitting on top of IP, just like in other parts of the internet now. It’ll be interesting to see how open the process is once they release code and start to work on it.

Basically it’s a wait and watch so really I’m ¯\_(ツ)_/¯

Zephyr RTOS 2.x on Fedora: Configure the build environment

It’s been a while since I’ve had time to play with the Zephyr RTOS project and the project has evolved greatly since so I thought I’d document the process I went through while playing with Zephyr 2.1 on Fedora using the Fedora native cross toolchains rather than the various ones suggested by the Zephyr Project docs.

I’m going to do a couple of posts in this series to break it up a little. This first one will be getting a generic build environment setup. I’ll go into more detail on the specific devices I’m playing with but the ones I have handy are ARM Cortex-M based so that’s what I’ll be focusing on even though Zephyr RTOS supports numerous architectures.

As before it’s worth reading the latest Zephyr Getting Started guide. This time around I’m using a AWS aarch64 a1.medium instance running a Fedora 31 cloud instance but I’ve also tested that a DigitalOcean Droplet with 2Gb RAM works with the later ZephyrRTOS releases too.

Once you have a Fedora instance up and running install the required dependencies:

# disable modularity, mostly just slows things down.
$ sudo sed -i 's/enabled=1/enabled=0/' /etc/yum.repos.d/fe*mod*

# install core utils, git and cross compilers
$ sudo dnf install git-core cmake ninja-build gperf dfu-util dtc \
xz file python3-pyelftools arm-none-eabi-gcc-cs python3-pip

# requirements for the west (Zephyr meta build tool)
$ sudo dnf install python3-colorama python3-configobj \
python3-configobj python3-docopt python3-pykwalify \
python3-dateutil python3-colorama python3-docopt \
python3-pykwalify python3-packaging

We now install west:

$ pip3 install --user --upgrade west

We now have key build dependencies installed so we can initialise west and clone key repos using west (this will take a little while to do an initial clone run):

$ west init zephyr
$ cd zephyr
$ west update

Setup the Zephyr environment for cross compiling with the distribution tools:

$ export ZEPHYR_TOOLCHAIN_VARIANT=cross-compile
$ export CROSS_COMPILE=/usr/bin/arm-none-eabi-
$ source zephyr-env.sh
$ mkdir builds

By default the above uses the git master branch of the Zephyr git repo. If you wish to use a stable branch you can just check it out. The latest stable release is, currently, 2.1 so to use this you can check out the stable branch:

$ git checkout v2.1-branch

With this we now have a Zephyr RTOS development environment setup for building for Arm Cortex-M based devices on Fedora using the distribution’s cross toolchains.

Raspberry Pi improvements in Fedora 29

So Fedora 29 is probably going to account for the largest single improvement to support on the Raspberry Pi support in Fedora since we added initial support in Fedora 25. It certainly wasn’t without issue, but after quite a bit of debug we’ve got the post release issues with the WiFi back to being stable!

WiFi improvements
The support for upstream NVRAM files and the ability to add those files to linux-firmware means we get WiFi support for the Raspberry Pi 3 Series of devices out of the box! No need to grab anything, it just works! Well mostly, we had some issues with WiFi being very intermittent, as well as a missed bug around aarch64 but now with the 4.19.10 kernel everything appears to be working and stable. This makes me very happy and it took longer than I had hoped but we’re there. This device specific NVRAM driver support will also help another bunch of cheap Arm and x86 based devices that ship with Broadcom/Cyprus based WiFi support moving forward.

ZRAM enabled by default
By supporting and enabling ZRAM swap by default we get a more responsive device and less wear on the MicroSD storage. Over all we’ve seen reasonable performance improvements and to no date no major issues.

GNOME performance improvements
In May 2018 the Raspberry Pi Foundation kindly hosted a GNOME Performance Hackfest in the lovely Cambridge. Over a couple of days we managed to fix a number of issues seen, review and document a number of issues and work on a number of ways of reducing the memory usage of GNOME. Of course this improvement is primarily seen constrained devices like the Raspberry Pi but ultimately less memory utilisation by GNOME even helps devices with decent amounts of RAM and CPUs too. The fixes didn’t arrive in time for Fedora 28, but a bunch have landed in Fedora 29 providing noticeable improvements, and the GNOME team is by no means done and there will be more coming in Fedora 30 and beyond! It was an excellent start and I expect there will be ongoing enhancements here into the future especially with devices like the Purism Phone which will have similar constraints.

Initial CPU frequency support
Another of the largest issues around the Raspberry Pi is complaints it was slow, part of the issue here is that there’s no upstream CPU Frequency driver which means all models of the Raspberry Pi run at a glacial, but safe, 600Mhz out of the box compared to the highest speed, which on the 3B+ is 1400Mhz. With Fedora 29 we’ve landed an experimental cpufreq driver which allows us to run the Raspberry Pi 3-Series at much closer to optimal speeds. While this is experimental it might not stay around if we find out it causes issues or ends up being a maintenance burden but to date it hasn’t yet appeared to have caused any issues.

HWmon Voltage Sensor
There’s a new driver that reports when the voltage supplied by the PSU drops below the required voltage. It can be a bit noisy in dmesg but one of the biggest support problems we have with the Raspberry Pis is people using a power supply that’s not powerful enough, this issue is more of a problem with Fedora 29 because with the support for running at faster frequencies due to the cpufreq driver it means we also draw more power and some PSUs that were previously fine now cause issues because they can’t supply enough current.

Enhanced support for config.txt
A lot of the hardware addons are supported in Raspbian are done by enabling things in the config.txt file, this in turn does things like loading DT overlays and merging them with the base DT to enable extra hardware like HAT support. We have enhanced the way Fedora works with this which enables us to be much closer to the way Raspbian handles these things. The advantage this has is that the documentation that’s written for Raspbian is then usable by Fedora in the wider Raspberry Pi ecosystem which in turn makes it easier for end users to get HW up and running due to less differences in process. There’s further enhancements to make here but every step closer is easier for everyone to enable and use their favourite HATs.

Improved bcm283x firmware support
In preparation for grub2 support we enhanced how we deal with the firmware that the Raspberry Pi uses for booting. This deals with the early startup. We never use to upgrade it by default to ensure things didn’t break, but it also meant most users also didn’t by default get the fixes and enhancements. Now we do. The config.txt is also handled directly which means if you never edit the file you now automatically get any changes we make, because rpm handles the file as a config file, if we change it you get a .rpmnew file so you won’t lose your changes.

Camera support
This wasn’t available in the Fedora 29 4.18 kernels, but with the rebase to the 4.19 kernel the support for the camera on the Raspberry Pi CSI Camera interface improved enough we could enable this in Fedora. The early 4.19 kernels don’t automatically detect and load support if the camera module is attached. There’s some patches in 4.20 in rawhide for this, and we’ll bring some of this to 4.19 soon, and we’re working with upstream to further improve the camera support. You’ll also want the latest bcm283x firmware which tweaks some of the config.txt and updates to a firmware with ISP fixes.

Another improvements
There was also a number of general Arm improvements which sped up crypto on the Raspberry Pi, improved the USB, fixed up some issues with the wired ethernet on the 3B+, power and a number of other fixes. As always there’s more coming. The 4.20 kernel rebase should also bring with it analog sound support early in the new year.

Conclusion
Overall I was pleased with the work that landed in Fedora over 2018 for the Raspberry Pi. The WiFi regression was disappointing, but now with that fixed in 4.19.10 we have WiFi support out of the box without users needing to download anything which moving forward will make things a lot more straight forward. The initial support for the camera makes it much more useful in numerous use cases and we’ll really polish up the HAT support in Fedora 30 which for me is the last remaining big ticket item for Raspberry Pi support. There’s still some annoying bits around the EDID detection in the display, but there’s work to improve that upstream, and also there’s work to land the media decode offloading upstream too which will also one of the few remaining bits.