Project update 3 of 15
During the last few months, based on feedback from beta customers and our own dog-fooding experiences, Ana and I redesigned almost all parts of MNT Reform, our libre laptop. We are now close to a concept that — we believe — will deliver on the promises of the campaign, in terms of modularity, openness, usability, and performance.
We’re going to upgrade the default System-on-Chip of Reform to NXP/Freescale i.MX8M. This wasn’t an easy decision, but we believe it is the right thing to do: deliver more performance and usability to you, at a better thermal/power envelope than what is possible with the aging i.MX6.
i.MX8M has four 64-bit ARM Cortex-A53 cores, an additional Cortex-M4F core, faster PCIe, USB3.0, a better GPU, and much higher memory bandwidth.
Unfortunately, during the boot process, i.MX8M requires a closed-source firmware for an embedded ARCompact processor in the Synopsys DDR4 PHY. This firmware, which is only a few kilobytes in size, is responsible for regulating the physical connection to the DDR chips in the face of changing temperatures. We are in contact with reverse engineers with the goal of analyzing what the capabilities of this so called PHY Utility Block (PUB) are, and to find out if we have a chance to replace this firmware at some point in the future.
On the bright side, all critically important subsystems of i.MX8M are already supported by free and open source drivers in the mainline Linux kernel, including the more powerful Vivante GC7000 GPU that is supported by the etnaviv driver project. No closed-source software drivers are required to run the system. Moreover, i.MX8M is currently the best documented modern ARM SoC. After creating an account on nxp.com, you can download the 6300 pages strong reference manual and learn about much of the chip’s details. And i.MX chips are well-known for their longevity: NXP advertises a production lifetime of at least 10-15 years.
There are some avoidable features of the i.MX8M that currently require binary firmware to work. The first one is the Cadence "HD Display TX" HDMI controller: it includes an Xtensa-based "uCPU" that apparently controls HDCP, DDC, and clocking for HDMI. You don’t need to use the HDMI port, though — an alternative is to connect a USB3.0 based HDMI or DisplayPort adapter with DisplayLink technology, for example. Unsurprisingly, the "Hantro" video decoder (for compressed video streams like H.265) in the chip needs proprietary firmware as well, as was already the case with i.MX6. If you want to avoid this firmware, you can use the CPU cores for video decoding, which requires more energy than using the mystery meat decoder, though.
All firmware used in Reform written by MNT — for the keyboard, trackball, and battery controller — is of course free and open source.
We are working towards a future where all critical components in your personal computing devices can be free and open source or at least well documented and under the exclusive control of the owner. Reform is designed for the long term, with upgradeability in mind. For example, when an affordable, high-performing RISC-V chip is released, we will design a motherboard version around it that you can swap into an existing Reform chassis.
The new Reform case is almost a centimeter thinner. And it is made up of only 5 major parts which are each CNC milled or bent/cut from aluminum. This makes the assembly of Reform much easier than before, while providing a more robust body structure at the same time. We will also deliver 3D-printable files of the case parts for those of you who would like to customize them.
We changed the motherboard layout to reach both the left and right sides of the case, so that we can have ports on both sides. This way, we can also include an SD card slot and more USB ports (which are now USB3.0). To be able to support future or third-party swap-in motherboards, we made the port covers interchangeable cut metal parts.
The display is upgraded from 11.6 inch 1366x768 LVDS panel to a 12.5 inch 1920x1080 eDP panel, which means less bezel and more resolution to work with.
Using the safe LiFePO4 battery chemistry in Reform turned out to be a success, but the pouch cells we used are not easy to source and service for customers. So we decided to go with a slightly more complex, but more reliable and — most importantly — customer serviceable battery system. The new Reform will be powered by 8 LiFePO4 cells in the standard 18650 form factor. Four of these will be connected in series to raise the base voltage to around 12 V, eliminating problems with low voltage and high currents. Using individual cells also means you can exchange battery cells on the fly, and you’ll be able to buy individual (or bulk) cells from third party vendors.
While the mechanical keyboard of Reform 0.4 was a good start, we still wanted to improve the look and feel, as well as the readability and quality of the keycaps. We decided to change from Cherry ML switches to Kailh Choc switches, which cost less, have better haptics, and even exist in different tactile/clicky flavors similar to the popular MX switches. To simplify our production workflow, we will not be producing our own keycaps, but source blanks directly from Kailh and have them labelled by a local specialist printing company in Berlin. Responding to user feedback, we also made the layout simpler and more ergonomic. By using only two different keycap sizes, we were able to eliminate the use of stabilizer wires and to achieve a more uniform look. We also moved the keyboard further to the back to allow for a larger palm rest area, and integrated the power switch with the keyboard.
The new Reform trackball is upgraded from two buttons to a whopping five buttons, so you don’t have to worry anymore about how to do a middle click or use the trackball as a scroll wheel. Of course, because our trackball firmware is open source, you can adjust the button functions to behave exactly as you like. The new mechanical design is also much more robust and the new enclosure improves the smooth travel of the ball. For the ball’s motion tracking, we are also evaluating new, thinner laser sensors. And we are working on a capacitive trackpad as an alternative for those of you who prefer it.
We had some unused space below the screen, and sound makes a computer feel more alive, so Reform will finally get integrated stereo speakers.
Pricing information will be available as soon as the new motherboard schematics are finished, followed by the launch of our crowdfunding campaign on Crowd Supply.
As before, your feedback and ideas are always welcome. Please write to email@example.com.
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