Marcin Juszkiewicz

For long time I had one project on my todo list: media player for my wife use. Has to be easy to use and control, does not need connecting anything when you want to watch a movie etc. Typical black box design.

Idea was to take one of boards I have at home, plug 750GB 2.5” hdd to it and put it on a box with only power and hdmi ports exposed. All running Ubuntu (with distro kernel) or Android. And controlled by simple remote control.

I tested several platforms as a base for it. First was Pandaboard — but as I have EA1 board it was far too slow for my use. And with current kernels there is no support for any hardware decoding or video acceleration (yay for PowerVR and yay for Texas Instruments). Then I purchased Wandboard Quad. Nice device, fast but I lacked patience to get it to properly recognize monitors so it always booted into XGA resolution. HW acceleration was a bit of fun as well.

Then I got Minnowboard Max from Dave Anders. After first days of playing with board it was visible that it can be a good platform for this project. But then something happened and board required RMA which took quite a long time (remember to pay for air transport of package while sending Europe->USA).

During last 2-3 weeks I was working on it in free time and finally got it done:

Box contents:

• Minnowboard Max (dualcore Atom with Intel GPU and 2GB ram)
• 750GB Serial ATA 2.5” hdd (bootloader, system, movies storage)
• cheap Realtek WiFi dongle
• cheap usb hub
• remote control dongle
• microhdmi/m -> hdmi/f cable
• hdmi/m -> hdmi/m adapter
• hdmi/f -> hdmi/f wall mountable adapter

Amount of HDMI adapters was required as finding microhdmi/m->hdmi/m cable is (probably) impossible.

USB hub was fun. I have several of those but this one got removed from case, got all cables desoldered (two going to second board with additional two ports and one going to host) and then fun started…

Only one connector had 2.54mm spacing while both host and second port one were some random size. After soldering single pins for host cable I decided to not add 4th port. Pictures show why ;D

That’s hardware. For software part I used Ubuntu 14.04 LTS with Kodi 14.2 ‘Helix’ as media center. After few small tweaks (automatic login to ‘kodi’ user and into ‘kodi’ session) system boots directly to movie selection.

But how to choose what to play? My Iogear wireless keyboard will not go with media player box… I bought Natec A30 airmouse but then it shown that it’s dpad buttons work only as IR control for TV ;( But then I realised that years ago I bought Sony bluetooth remote for Playstation 3 console (for some other random project). And it still works ;D

Still have to sort out key mapping as lot of remote buttons have no sense for media center (I have no idea what for those triangle/circle/box/cross are for example) but this is small part which I already have partially solved. And need to add BT dongle into the box to get it working ;D

Everyone can grab and install Fedora 21-22 on APM Mustang. But what if you want something more enterprise ready? Answer is simple: you can install CentOS 7 (at Alpha stage now).

Requirements are simple:

• APM Mustang (AMD Seattle should be fine as well)
• USB thumb drive (512MB is enough)
• network access
• CentOS 7 Alpha installation iso for AArch64
• serial cable

First fetch iso and then copy to USB thumb drive (simple “dd if=boot.iso of=/dev/sdc bs=4M” is enough). Then just reboot to UEFI shell and run “FS1:EFIBOOTBOOTAA64.EFI” to get into installation.

All files will be read from USB (for Mustang you need official APM firmware 1.1.0 to get proper DTB) and installation goes like with Fedora, RHEL, CentOS — standard Anaconda.

Finally reboot and system is ready for use:

CentOS Linux 7 (Core)
Kernel 4.0.0-1.el7.aarch64 on an aarch64

pinkiepie login:

AArch64 port is now in progress so not all packages are built yet but they will be.

There are moments when more than one machine would be handy. But AArch64 computers are not yet available in shop around a corner we have to go for other options. So this time let check how to get virtual machines working.

Requirements

For this I would use Fedora 22 on APM Mustang (other systems will be fine too). What else will be needed:

• libvirtd running
• virt-manager 1.1.0-7 (or higher) installed on AArch64 machine
• UEFI for AArch64 from Gerd’s Hoffmann firmware repository
• Fedora or Debian installation iso (Ubuntu does not provide such)
• computer with X11 working (to control virt-manager)

UPDATE: starting from Fedora 23 UEFI package is in distribution repository. Packages are ‘edk2-arm’ for 32bit arm, ‘edk2-aarch64’ for 64bit arm and ‘edk2-ovmf’ for x86-64 architecture.

Is KVM working?

First we need to get KVM working — run “dmesg|grep -i kvm” after system boot. It should look like this:

hrw@pinkiepie-f22:~$ dmesg|grep -i kvm
[    0.261904] kvm [1]: interrupt-controller@780c0000 IRQ5
[    0.262011] kvm [1]: timer IRQ3
[    0.262026] kvm [1]: Hyp mode initialized successfully

But you can also get this:

[    0.343796] kvm [1]: GICV size 0x2000 not a multiple of page size 0x10000
[    0.343802] kvm [1]: error: no compatible GIC info found
[    0.343909] kvm [1]: error initializing Hyp mode: -6

In such case fixed DeviceTree blob from bug #1165290 would be needed. Fetch attached DTB, store as “/boot/mustang.dtb” and then edit “/etc/grub2-efi.cfg” file so kernel entry will look like this:

menuentry 'Fedora (4.0.0-0.rc5.git4.1.fc22.aarch64) 22 (Twenty Two)' --class fedora --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-4.0.0-0.rc5.git2.4.1.fc22.aarch64-advanced-13e42c65-e2eb-4986-abf9-262e287842e4' {
        load_video
        insmod gzio
        insmod part_gpt
        insmod ext2
        set root='hd1,gpt32'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd1,gpt32 --hint-efi=hd1,gpt32 --hint-baremetal=ahci1,gpt32  13e42c65-e2eb-4986-abf9-262e287842e4
        else
          search --no-floppy --fs-uuid --set=root 13e42c65-e2eb-4986-abf9-262e287842e4
        fi
        linux /boot/vmlinuz-4.0.0-0.rc5.git4.1.fc22.aarch64 root=UUID=13e42c65-e2eb-4986-abf9-262e287842e4 ro  LANG=en_GB.UTF-8
        initrd /boot/initramfs-4.0.0-0.rc5.git4.1.fc22.aarch64.img
        devicetree /boot/mustang.dtb
}

After reboot KVM should work.

Software installation

Next step is installing VM software: “dnf install libvirt-daemon* virt-manager” will handle that. But to run Virt Manager we also need a way to see it. X11 forwarding over ssh to the rescue ;D After ssh connection I usually cheat with “sudo ln -sf ~hrw/.Xauthority /root/.Xauthority” to be able to run UI apps as root user.

UEFI firmware

Next phase is UEFI which allows us to boot virtual machine with ISO installation images (compared to kernel/initrd combo when there is no firmware/bootloader possibility). We will install one from repository provided by Gerd Hoffmann:

hrw@pinkiepie-f22:~$ sudo -s
root@pinkiepie-f22:hrw$ cd /etc/yum.repos.d/
root@pinkiepie-f22:yum.repos.d$ wget https://www.kraxel.org/repos/firmware.repo
root@pinkiepie-f22:yum.repos.d$ dnf install edk2.git-aarch64

Then libvirtd config change to give path for just installed firmware. Edit “/etc/libvirt/qemu.conf” file and at the end of file add this:

nvram = [
   "/usr/share/edk2.git/aarch64/QEMU_EFI-pflash.raw:/usr/share/edk2.git/aarch64/vars-template-pflash.raw"
]

Restart libvirtd via “systemctl restart libvirtd“.

Running Virtual Machine Manager

Now we can connect via “ssh -X” and run “sudo virt-manager“:

Next step is connection to libvirtd:

Now we are ready for creating VMs. After pressing “Create a new VM” button we should see this:

And then creation of VM goes nearly like on x86 machines as there is no graphics only serial console.

But if you forgot to setup UEFI firmware then you will get this:

In such case get back to UEFI firmware step.

Installing Fedora 22 in VM

So let’s test how it works. Fedora 22 is in Beta phase now so why not test it?

2GB ram and 3 cpu cores should be more than enough ;D

And 10GB for minimal system:

But when it went to serial console it did not look good :(

I realized that I forgot to install fonts, but quick “dnf install dejavu*fonts” sorted that out:

Go for VNC controller installation.

After installation finish system runs just fine:

Summary

As you can see Fedora 22 has everything in place to get VM running on AArch64. UEFI firmware is the only thing out of distribution but that’s due to some license stuff on vfat implementation or something like that. I was running virtual machines with Debian ‘jessie’ and Fedora 22. Wanted to check Ubuntu but all I found was kernel/initrd combo (which is one of ways to boot in virt-manager) but it did not booted in VM.

Git is now ten years old. More and more developers get lost when have to deal with CVS or Subversion as first SCM they learnt was git. But in daily work I see many people limited to very basic use of it ;(

There is a lot of commands and external plugins for git. I do not want to mention them but rather concentrate on ones installed as part of git package. And only those which I think EVERY developer using git should know that they exist and how to use them.

Dealing with repositories

Dealing with other repo is easy set: “pull” to merge changes (“fetch” if you only want to have them locally), “push” to send them out. “git remote” is useful too.

Branching your changes

Branching is easy and there is a lot of articles how to do it. Basically “git branch” to see which one you use, “git branch -a” to check which are available and “git checkout” to grab code from one.

Looking at changes

Checking changes is next step. “git diff” with all variants like checking local not committed changes against local repo, comparing to other branches, checking differences between branches etc. “git log -p” to check what was changed in earlier commits.

Then goes “status” to see which local files are changed/added/removed and need attention. And “add”, “rm” and finally “commit” to get all of them sorted out.

Lot of people ends here. The problem appears when they get patches…

Handling single patches

So how to deal with patches in git world? You can of course do “patch -p1 <some.patch” and take care of adding removing files and doing commit. but git has a way for it too.

To generate patch you can use “git diff” and store output into file. But this will lack author information and description. So it is better to commit changes and then use “git format-patch” to export what you did into file. Such file can be attached to bug tracker, sent by email, put online etc. Importing it is simple: “git am some.patch” and if it applies then it is merged like you would do local commit.

There are other ways probably too. Quilt, stgit etc. But this one is using basic git commands.

And I still remember days when I thought that git and me do not match ;D

During Linaro Connect 2015 Asia there was announcement about new Linaro project called “96boards”. It is about making cheap ARM/AArch64 boards in same form factor and same placement of ports. And first board named HiKey was presented. Today third one — from Qualcomm. So we have two boards now (2/96 was not yet announced).

I prefer not to comment on form factor, lack of Ethernet, mobile phone cpus and other things people do not like but about software requirements.

96boards specification v1.0 says:

Minimum Software requirements for 96Boards certification will include:

• Boot architecture (open source implementations are strongly recommended)
• Support for bootloader such as U-Boot/FDT, UEFI/ACPI, UEFI/FDT
• Support for a secure execution environment (optional)
• Support for ARM Trusted Firmware (ARMv8), including PSCI APIs (optional)
• Accelerated graphics support
• Accelerated graphics drivers need to be fully supported either with open source code, or through royalty free binary drivers. If binary drivers are utilized, the vendor will provide support to provide updated drivers/libraries to support new mainline Linux kernel features.
• Kernel
• A kernel based on one of the following that is buildable from source code and any required binary blobs:
• kernel.org latest “mainline” or “stable” kernel
• The latest Google-supported Android kernel version
• One of the last two kernel.org LTS kernels (for example Linaro LSK)
• Operating system
• The latest released (stable) version of one or more of the following open source distributions shall be made available for a 96Boards CE compliant design:
• Android
• Debian or Ubuntu
• Fedora or Red Hat
• An OpenEmbedded/Yocto build of a Linux distribution

I hoped that Linaro will be a place where free/open source software would matter. But it looks like “let release whatever you want as long as size and ports match” deal. Any blob as bootloader, binary graphics drivers (does someone remember TI OMAP line and PowerVR? Those boards run with raw framebuffer nowadays).

And that kernel requirement… HiKey uses cpu which is not in mainline kernel, so does Qualcomm one. Are they in AOSP kernel? Maybe. But does someone else than Android uses those trees for serious work? Latest I see in kernel-msm (which may not be proper place to check) is 3.10 which was released (in mainline) nearly 2 years ago…

I really wonder how “latest released (stable) version” of Debian/Fedora/Ubuntu can be made available for those boards when all those distributions use mainline kernel only (I do not count user generated remixes which are not supported by anyone).

So I wonder will 96/96 board came with mainline support, open bootloader and open drivers for everything. Time will show. Until that I am not so interested.

For something about 15 years I was using Debian distribution and ones which derived from it (like Ubuntu). Basically whole time I used development versions of them and amount of issues was nearly not existing. Now I run Rawhide…

For those who do not know: Fedora world contains four distributions: Fedora, RHEL, CentOS and Rawhide. All new stuff goes to Rawhide which is then branched to make Fedora release. Every few years Red Hat forks released Fedora and uses it as a base for new RHEL release. Then CentOS guys create new release based on RHEL. At least this is how I see it — others will say “but rawhide is fedora”.

I think that the problem lies in development model. All new stuff goes to Rawhide but at same time nearly no one is using it anything can happen there. For example my KDE session lacks window decorations, Konsole5 freezes on any window resize and the common answer for such issues is “You should expect that in rawhide”.

Going into Fedora irc channels with questions is just waste of TCP/IP pockets because in a moment when you mention rawhide it is like everyone fired /ignore on you.

And it is some kind of fun (for some sick/weird definition of it) to watch how people start development of packages just after Fedora releases something. They upgrade and then start to seek what interesting happens in rawhide and can be built.

Each day I am closer to go back to Debian/Ubuntu for a desktop with just keeping Fedora in VM for development of some packages.

So today Linaro announced their first board from 96boards project. It is named HiKey and is based on HiSilicon cpu for mobile phones.

I had an occasion to see that board during FOSDEM and decided to write something about it after it land on my desk (which will happen sooner or later). But I have read specification for this and next boards and decided to write few words from my perspective.

First thing? Footprint. Good that two sizes are available for designs as not everyone may want to squeeze into small one.

Second? Ports. 2015 year and no Ethernet, no SATA? Sure, first board is based on SoC from a mobile phone but there is no place on small board for them and extended version looks like not allow for extra ports too.

Next? Power supply. 8-18V in a world where everything is on 5V already. The only place where 12V is mentioned in spec is “external fan power”.

So as we are on voltage… Serial at pins and 1.8V level. Nice way of forcing everyone to buy new serial dongle (Arduino ones are 3.3 or 5V).

But assume that we got it powered and have serial connected. How to boot it? According to specs mainline kernel (or AOSP one or LTE one) has to be used. I wonder how HiSilicon cpu is supported in any of those. From what I read during day (on quite slow connection) it is still not in a kernel…

Graphics situation is still shitty. Vendor is allowed to provide binary blobs to get display working. Did they not learnt from OMAP? PowerVR again someone? But sure, plain framebuffer is all you need. OpenGL is for weak.

I prefer not to discuss about selection of signals on low/high connectors. There are more capable people for it. I only wonder why 2mm raster where nearly all boards I had played with had 2.500 one.

I like list of distributions listed as ones to choose. No longer Android/Ubuntu but also Debian, Fedora or OpenEmbedded based one

But give them time. It is just first board and next ones are announced. Marvell will produce one (they are in a Linaro group for it), other will (probably) follow. Hope that there will be something better.

Today Dennis Gilmore asked me on #fedora-arm “Are you a packager in Fedora?” so I answered that I am in “packager” group but do not own a package in Fedora and do not have plans to change it.

It turned out that the question was part of thinking that maybe I should get membership in the secondary arch group which would allow me to commit my fixes directly. Normally I prefer to grab maintainer’s attention with new reported bug or even IRC discussion about an issue. But sometimes there is no response and fix is aarch64 related without any changes for primary architectures.

So now I can commit fixes to Fedora packages directly to git repositories. Will not overuse this privilege and make it only when it is really required.