Install openSUSE Tumbleweed + KDE on MacBook 2015

It is pretty easy to install openSUSE Linux on a MacBook as operating system. However there are some pitfalls, which can cause trouble. The article gives some hints about a dual boot setup with OS X 10.10 and at time of writing current openSUSE Tumbleweed 20170104 (oS TW) on a MacBookPro from early 2015. A recent Linux kernel, like in TW, is advisable as it provides better hardware support.

The LiveCD can be downloaded from and written with ImageWriter GUI to a USB stick ~1GB. I’ve choose the Live KDE one and it run well on a first test. During boot after the first sound and display light switches on hold Option/alt key and wait for the disk selection icon. Put the USB key with Linux in a USB port and wait until the removable media icon appears and select it for boot. For me all went fine. The internal display, sound, touchpad and keyboard where detected and worked well. After that test. It was a good time to backup all data from the internal flash drive. I wrote a compressed disk image to a stick using the unix dd command. With that image and the live media I was able to recover, in case anything went wrong. It is not easy to satisfy OS X for it’s journaled HFS and the introduced logical volume layout, which comes with a separate repair partition directly after the main OS partition. That combination is pretty fragile, but should not be touched. The rescue partition can be booted with the command key + r pressed. External tools failed for me. So I booted into rescue mode and took the OS X diskutil or it’s Disk Utility GUI counter part. The tool allows to split the disk into several partitions. The EFI and the rescue ones are hidden in the GUI. The newly created additional partitions can be formatted to exfat and later be modified for the Linux installation. One additional HFS partition was created for sharing data between OS X and Linux with the comfortable Unix attributes. The well know exfat used by many bigger USB sticks, is a possible option as well, but needs the exfat-kmp kernel module installed, which is not by default installed due to Microsofts patent license policy for the file system. In order to write to HFS from Linux, any HFS partition must have switched off the journal feature. This can be done inside the OS X Disk Utility GUI, by selecting the data partition and holding the alt key and searching in the menu for the disable journaling entry. After rebooting into the Live media, I clicked on the Install icon on the desktop background and started openSUSE’s Yast tool. Depending on the available space, it might be a good idea to disable the btrfs filesystem snapshot feature, as it can eat up lots of disk space during each update. An other pitfall is the boot stage. Select there secure GrubEFI mode, as Grub needs special handling for the required EFI boot process. That’s it. Finish install and you should be able to reboot into Linux with the alt key.

My MacBook has unfortunedly a defect. It’s Boot Manager is very slow. Erasing and reinstalling OS X did not fix that issue. To circumvent it, I need to reset NVRAM by pressing alt+cmd+r+p at boot start for around 14 second, until the display gets dark, hold alt on the soon comming next boot sound, select the EFI TW disk in Apple Boot Manager and can then fluently go through the boot process. Without that extra step, the keyboard and mouse might not respond in Linux at all, except the power button. Hot reboot from Linux works fine. OS X does a cold reboot and needs the extra sequence.

KDE’s Plasma needs some configuration to run properly on a high resolution display. Otherwise additional monitors can be connected and easily configured with the kscreen SystemSettings module. Hibernate works fine. Currently the notebooks SD slot is ignored and the facetime camera has no ready oS packages. Battery run time can be extended by spartan power consumption (less brightness, less USB devices and pulseaudio -k, check with powertop), but is not too far from OS X anyway.

Digital diaphragm for optical lenses

In photography most optical lenses use mechanical diaphragms for aperture control. They are traditionally manufactured from metal blades and works quite good. However metal blades exposes some disadvantages:

  • mechanical parts will sooner or later fail
  • the cheaper forms give strong diffraction spikes
  • manufacturers need more metal blades for a round iris, which is expensive
  • a metal blade with its sharp edges give artefacts, which are visible in out of focus regions.
  • but, contrast is very high by using opaque metal

In order to obtain a better bokeh, some lenses are equipped with apodization filters. Those filters work mostly for fully open arperture and are very specialised and thus relatively expensive.

A digital arperture build as a transparent display with enough spatial resolution can not only improve the shape of the diaphragm. It could feature as a apodisation filter, if it supports enough gray levels. And it can change its form programatically.

Two possible digital diaphragm forms:

  • leverage existing display technology
  • better aperture shape for reduced artefacts
  • apodisation filter on demand for best bokeh or faster light
  • programmable or at least updateable aperture pattern (sharp/gausian/linear/…)
  • no metal blades or other mechanical parts to fail
  • over the years get cheaper than mechanical counterpart
  • reduce number of glas to air surfaces in optical lens design
  • integratable aperture into lens groups
  • display transparency increases quickly and is for OLED at 45% by 2016, which means at the moment just one f-stop
  • mobile demands high display resolutions anyway

The digital arperture can easily be manufactured as a monochrome display and be placed traditionally between two optical lens groups, where today the diaphragm is located. Or it is even possible to optically integrate the aperture into one lens group, without additional glas to air surfaces, as is needed with moving blades. Once the optical quality of the digital filter display is good enough a digital diaphragm can be even cheaper than a high quality mechanical counterpart.

Reanimation of MacBook Air

For some months our MacBook Air was broken. Finally good time to replace, I thought. On the other side, the old notebook was quite useful even 6 years after purchasing. Coding on the road, web surfing, SVG/PDF presentations and so on worked fine on the Core2Duo device from 2008. The first breaking symptoms started with video errors on a DVI connected WUXGA/HDTV+ sized display. The error looked like non stable frequency handling, with the upper scan lines being visually ok and the lower end wobbling to the right. A black desktop background with a small sized window was sometimes a workaround. This notebook type uses a Nvidia 9400M on the logic board. Another non portable computer of mine which uses Nvidia 9300 Go on board graphics runs without such issues. So I expected no reason to worry about the type of graphics chip. Later on, the notebook stopped completely, even without attached external display. It showed a well known one beep every 5 seconds during startup. On MacBook Pro/Air’s this symptom means usually broken RAM.

The RAM is soldered directly on the logic board. Replacing @ Apple appeared prohibitive. Now that I began to look around to sell the broken hardware to hobbyists, I found an article talking about these early MacBook Air’s. This specific one is a 2.1 rev A 2.13 GHz. It was mentioned, that early devices suffered from lead-free soldering, which performs somewhat worse in regards to ductility than normal soldering. The result was that many of these devices suffered from electrical disconnections of its circuitry during the course of warming and cooling and the related thermal expansion and contraction. The device showed the one beep symptom on startup without booting. An engineer from Apple was unofficially cited to suggest, that putting the logic board in around 100° Celsius for a few minutes would eventually suffice to solve the issue. That sounded worth a try to me. As I love to open up many devices to look into and eventually repair them, taking my time for dismounting the logic board and not bringing it to a repair service was fine for me. But be warned, doing so can be difficult for beginners. I placed the board on some wool in the oven @120 ° and after 10 minutes and some more for montage, the laptop started again to work. I am not sure if soldering is really solved now or if the experienced symptoms will come back. I guess that some memory chips on the board were resetted and stopped telling that RAM is broken. So my device works again and will keep us happy for a while – I hope.

Magic Lantern @ LGM in Leipzig

… on Wednesday April 2nd. Their talk will begin 18:30 o’clock local time in the New Paulinum of the University of Leipzig.

Magic Lantern was started in 2009 by Trammel Hudson to bring professional video recording and advanced photographic features to Canon EOS DSLR cameras.

The project expanded and its feature set. Custom video overlays, raw video recording, time lapsed video, manual audio control and more belong to it. With these tools Magic Lantern greatly improved useability in many areas upon bare Canon firmware and is now daily used by many professional photographers, journalists and movie makers.

Lenovo business Sollbruchstelle?

One year ago I wrote about the Lenovo Thinkpad Tablet based on Tegra II. After 12 months + the device is now pretty doomed. Not only mechanical switches stop working, the power supply gave up around the same time. Looks like Lenovo sells cheap and crappy hardware for business prices. For a ThinkPad labeled device that is far behind any expectations. But the whole concept behind Lenovos business tablets is flawed.

The manufacturer delivered since quite some time no security updates. The device boots only OS kernels digitally signed by Lenovo. So business administrators can not fix anything on their own as is otherwise usual for Android. That lockout makes just junk in a business environment. Further the company decided to build upon a Windows only chipst for the ThinkPad 2 Tablet, without any plans for migration of investments in Android. The minimum would have been a dual boot machine for those, who prefer to continue with, what they have build already. This is a business reset decision inside Lenovo. One simple measure would be to make the kernel signature public available to allow for security and OS updates on the device on a professional base. An other important step is to open up the currently Windows only ThinkPad 2 tablet for Android.

Sirko’s Laptop arrived

In july we started a pledgie to collect money to get a new work horse for Sirko Kemter. He is a artist, author and event organiser with strong involvement in open source . He was far too long in need to work on a reliable machine, which can be taken to conferences and workshops. His laptop arrived on 25th september 2012.

We are happy about the great response of the community and like to thank everybody who donated or raised awareness about the campaign. Much luck and fun with your new mobile workplace, Sirko.

Linux Desktop on Thinkpad Tablet

By default Lenovo completely forbids users who want to do their work in obtaining root rights through the Lenovo signed only booting on the ARM/Tegra based Thinkpad Tablet. The company does not provide any public means to it’s users, in order to circumvent the lock out of first class admin rights or to install alternative OSes. Fortunately a exploit including a tutorial was published end of January to workaround the signed booting. That way I obtained my basic user right back, that is to adapt the OS on my own device. People might argue that I could have bought a alternative device of a more customer friendly vendor. And I heard of a HTC tablet, which features a similar good display and stylus input. HTC enabled users for root access begin of this year. But I already obtained the Lenovo last year. The WeTab with it’s relatively open OS was interesting too. But as colour matters to me, I never came around it’s display.

Anyway, the little tablet is now running the XChat IRC client. And I am totally happy with it, as it serves it’s main purpose now as a well featured and productive communication client, which was not possible with Android alone. A patched tightVNCserver with Hacker’s Keyboard serves me well as interface to a chrooted Linux. Again I can enjoy side by side windows on a Linux desktop. The 10” device at the resolution of a desktop monitor provides enough space for that. A light wight and working web browser is Midori. For email I switch currently to K-9 Mail on Android. PDF and office documents are good readable in Android. gcc, gitk, terminal and so on work as expected. Oyranos builds fine.

It is nice to have practical two OSes on one device and use the advantages of both.

Update [March 22, 2012]: here is a ICC profile of the Lenovo Thinkpad Tablet inbuild monitor.

An other Open Source Colorimeter

Richard Hughes, the author of colord, developed in the recent months new hardware for measuring monitor colours. The ColorHug called device shall come at a relatively low price. It shall be useable for LCD/LED monitors providing input to calibration and profiling software. The most wide spread open source colour management system, which can create ICC profiles from colour measurements, is Argyll.

ColorHugThe author Richard Hughes states on his blog entry: “Existing hardware is proprietary and 100% closed, and my hardware has a GPL bootloader, GPL firmware image and GPL hardware schematics and PCBs”. The “100%” is a wrong marketing claim as Richard Hughes should know as Argyll user. However the new device fits nicely into a row with prior open source art in colorimeter hardware like the HCFR. The HCFR is supported in Argyll since some years now. To make the new ColorHug device functional, it would be great, if the hardware author could deliver a module instantly useable in Argyll.

What would now be interesting is to know, how the new device will compare with pre existing ones, being them proprietary or open source licensed hardware. The author gave a hint about speed. But speed is only one property useable to reduce noise in dark readings. Much more interesting is colour accuracy.

What is colour accuracy and why is it so important for a colorimeter like the HCFR or the new ColorHug? Colorimeter devices suffer almost all from a difference to the ideal colour reception of human eye, especially the cheaper ones. Only spectrometers can compensate better for that effect of non perfect filters in front of the actual light sensors, but expose other disadvantages. Colorimeter devices, which perform close to human sensibility, are usual expensive. Some are even more expensive than colour spectrometers. Colorimeter manufacturers use a common trick and put a correction matrix inside the device, which shall compensate for the difference between the sensitivity of human eyes and the colorimeter. But many users complained not to be able to get good results despite. This is easily understandable, as monitors emit light with very different spectral characteristics, which do not match the used filter in the colorimeter and its matrix. One approach to get better results is to use a per monitor model compensation matrix. Fortunately Argyll has implemented compensation matrices in one of its recent releases. The requirement for this approach to work is, that the data base needs input data from users.

Linux @ MacBookAir2,1

Some time ago I bought a new workstation for my home workplace. Its a reduced but lightwight laptop to run all major OSes. Here are some notes to make it useable under Linux. I installed openSUSE-11.2 on it both the hard way and much more recommended the easy one with the Superdrive which enables booting a non osX CD/DVD.

I simply placed Grub in the master boot record. Holding the option key, the left alt key, during boot can select osX if its needed. The 2.6.31 kernel seems to have problems booting the system. He stops very often with ACPI as last message. Boot options seem to play less of a role for that. However I have set apm=off. On my model it helps to remove all USB connections. Luckily there is only one USB connector possible. After starting the laptop and the first sound is heared or the screen becomes white I hit the power button to switch the laptop off. After pressing the power button again the system finally starts. I do not know why the MBA needs such a ceremony, but it helps at a rate of ~90%. Otherwise starting fails at around 90% or more. If USB does not work the four key reset combo helps with a switched of device. It is up+ctrl+alt + power. The green LED in the power cord should dim during that reset.

The keyboard can be set in the KDE4 systemsettings panel in the Country and Language tab -> keyboard layout. I use the Apple Laptop layout and some Macintosh option.

The Apple Superdrive is a small DVD drive designed solely for the MBA. It needs some power up help. The following code enables the drive under Linux:

The nvidia driver is recommended. I tested VDPAU and OpenGL which work fine. For connecting a external monitor one needs to open the nvdia-settings GUI and push in the “X Server Display Configuration” tab the “Detect Displays” button. Then the new monitor can be arranged and Xinerama is up to date. KDE is quite positive about that behaviour. The miniDisplayPort to DVI connector is needed for that to work.
The backlight does work with pommed. But due to a bug in Nvidias 190.53 driver changing the backlight works only in console mode. There are no problems with the nv driver in this regard. pommed enables as well the keyboard background light.

The sound card can be used with the MCP79 module. Set the model option to mb5. Sometimes the sound is set to mute. With kmix or alsamixer this can be unmuted.

Hypernate works, but only by explicitely choosing. On awake the nvidia driver takes some seconds to get back from intensive flickering to normal operation.

The internal broadcom wireless chip is a BCM4328. dmesg on the commandline will show. The binary driver can be downloaded from the manufacturer here

Additionally I have to blacklist the ssb driver. ndiswrapper is not needed.

The cheap inbuild camera workes in cheese without additional configuration.

So I think the support is pretty complete even with some manual interaction. Once Linux runs it reports to last over 5 hours under KDE with compiz without power cord. This of course only while reading some text. One might switch off the wireless and dim the backlight to get there.

Most unpleasant is the need to do some boot magick and a boot delay of half a minute. As well it is a schame for Apple to require the SuperDrive to boot from other vendors boot disks. All USB or other DVD drives are artifical blocked by Apple engineers through the computers internal firmware. So add the SuperDrive to your list of needed adds to the nacked MBA and take Apples marketing with a pinch of salt. All in all I would not have bought hardware that behaves such close minded for booting other operating systems when I had no need for osX.

HP’s DreamColor displays and the 30-bit advancement

10-bit per channel powered by modern graphic chips. Given the last generations of chips with high bit depth frame buffers, dual link dvi and HDMI it seems not so astonishing. Anyway HP can be praised to have brought this to designers and graphics studios at a reasonable price. Congratulation. (Of course I hope this technology becomes pretty standard and will become even more affordable.) Would be interessting to know how Dreamworks deploys this under Linux – Ati : Nvidia?