Archive for the 'Hardware' Category

Setting Sun SPARC video mode in OpenFirmware

Wednesday, August 19th, 2020

Some, older video drivers specific to proprietary Sun video boards such most of their early once but also one of the last of it’s kinds Creator / Elite 3d do not have a mode-setting open source Linux driver. To set another video mode for those you “currently” need to do so from the OBP / OpenFirmware, such as:

setenv output-device screen:r1600×1000x66

Unfortunately usually the cards open firmware glue does not support any arbitrary mode with this so you need to check against a list of officially Sun supported modes, … :-/ However, you can at least test what you set with

install-console

though ;-)

OpenLDI graphic cards

Thursday, August 13th, 2020

Once upon a time, in a galaxy far away the first digital flat panel (DFP) displays where digitally connected not by DVI, butOpen LDI: a high-bandwidth digital-video interface standard for connecting graphics/video processors to flat panel LCD monitors. It was based on the FPD-Link specification, which was the standard for transferring graphics and video data through notebook hinges since the late 1990s. Both OpenLDI and FPD-Link use low-voltage differential signaling (LVDS) as the physical layer. The SGI 1600SW was the only monitor produced in significant quantities with an OpenLDI connection (though it had minor differences from the final published standards):

While there where not many display, there were a couple of non-Sgi PC graphic cards that included OpenLDI:

  • #9 Revolution IV-FP
  • 3Dlabs Oxygen VX1-1600SW
  • Auto reconnect Bluetooth devices on Linux

    Tuesday, December 17th, 2019

    If you were wondering why your Bluetooth devices, such as keyboard and mouse, (…) do not automatically reconnect when you reboot / start your Linux desktop, … It is not enough to just have the bluetooth deamon running. You also need to power it up:

    libexec/bluetooth/bluetoothd
    bluetoothctl power on

    You obviously had to pair and connect the device, before but you also need to trust (because obviously “pairing” is not trusting) …

    bluetoothctl scan on
    bluetoothctl pair MM:AA:CC:..
    bluetoothctl connect MM:AA:CC:..
    bluetoothctl trust MM:AA:CC:..

    You also need to enable AutoEnable, in /etc/bluetooth/main.conf

    [Policy]
    AutoEnable=true

    Certainly would be too easy in 2019 for stuff to work without reading some freaking manual pages, and internet re-searching the topic a bit, … :-/

Enabling SSH on a head-less Raspberry Pi

Wednesday, September 25th, 2019

in the usually FAT boot partition create (e.g. touch) a file name “ssh”, and just place your wpa configuration file onto it as well, like:

country=FR
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network={
ssid=”NETWORK”
psk=”PASSWORD”
}

Some websites suggest a shorter, more minimal file without the country=YOUR-LOCATION, however the last time I checked that will not enable the wireless network interface, maybe intentionally due to regulatory concerns.

Let’s talk micro kernels

Thursday, February 14th, 2019

Over four years ago I wrote about Why monolithic kernels are fail and last night I live streamed some talk about micro kernels:

And in my famous prior art patent voiding serious I wanted to formerly disclose a potentially novel system call implementation detail idea: In multi server micro kernels context switches happen more frequent than in simple, shared address space monolithic kernel (such as Linux). This is due to device drivers (and filesystem, network stacks and hopefully everything else, ..!) hopefully running in regular, isolated processes. This is obviously great for security and stability, but naturally requires way more context switches that can hurt performance. Now slim and lightweight micro kernels (such as L4) are usually quite optimized and often require less instruction cycles for inter address space context switches, however such a horde of multiple servers will execute multiple times more of those. Now my (novel?) idea to further minimize the costs of context switches is to bundle system calls in batches (or molecules? ;-) so that an application (or device driver, after all they should now be regular processes, …!) only context switch once for a couple of system calls. The exact ABI calling convention and format has to be defined by the implementor and implementation, for simplicity let’s assume some kind of “protocol buffer”, so a open, read, seek, read sequence could look like:

syscallnr | arg0 | arg1 | arg2 | …
read | fd | buffer | 128
seek | fd | -128 | SEEK_END
read | fd | buffer | 128

The same concept obviously applies to all kind of similar operations, and is somewhat similar to the existing Unix concept of writev(), and it’s iovec structure – just way more generic and flexible.

As a bonus point for more flexibility, one could either implement it so, that the syscalls are executed one-by-one until the first error, or optional –for a little more flexibility– introduce flags / tags of groups to execute until and error occurs or not. E.g. the operations might be related to two different file descriptors, so the other tagged group could still be executed, even when one of them failed. Obviously error checking for the calling application becomes a multi return value operations, instead of just a single if (!read/write/…) {} block.

Still searching for the perfect laptop…

Monday, January 14th, 2019

Over a decade, 12 years (!!!) ago I wrote about who designs this crap (this millenniums laptops). And here we are the Apple MacBooks became even more unusable, with soldered in RAM, SSD, really crappy keyboards, that get stuck by mere dust. And while I would love a nice generic quality PC, there is always something wrong with each and every model. Thermal throttling, crappy keyboards, too. You name it. It is no wonder that PC sales are declining when users can not find a good and matching device:

Linux on macOS w/ Xhyve & Hypervisor.framework

Saturday, December 8th, 2018

Just the usual quite note for myself ;-)

xhyve -A -m 512m -c2 -f kexec,~/Downloads/boot64/vmlinuz_4.19.4-dist,initrd2,”earlyprintk=serial console=ttyS0 root=/dev/vda1″ -s 0:0,hostbridge -s 31,lpc -l com1,stdio -s 2,virtio-blk,~/Downloads/linux-vm.img -s 4:0,virtio-net -s 5,fbuf,tcp=127.0.0.1:29000,w=1024,h=768

AHCI PCIe SSDs

Sunday, October 7th, 2018

I thought we went from SATA connected (to AHCI board controllers) straight to PCIe connected NVMe protocol. Turns out there was a short time of PCIE connected SSDs with an AHCI controller. And of course Apple used them:

One can never have enough dongles^W proprietary connectors to lock users out, ..! :-/

Finally the first AMD ThinkPad!

Friday, September 21st, 2018

For decades fans of AMD, the inventor of x86-64, GPU infused APUs, and avoiders of a 100% Intel x86 monopoly where longing for a really high end quality machines, like IBM^W Lenovo ThinkPads. The dream came finally true, with AMD Ryzen w/ Vega gfx ThinkPads A285 and A485 this year.

This is a developing story, we will update with a review in a day or two.

Resist NVidia, especially for Linux

Friday, September 7th, 2018

So I do Linux kernel, driver, libraries, gcc, development since 1998. A little bit everywhere, all over the place. X86, ARM, PowerPC, SPARC you name it. I contributed to the Linux distribution ROCK Linux, later became stable release maintainer, and still run the fork #t2sde for embedded and special custom Linux distributions. My company ExactCODE was involved in many embedded projects and development like that, and in 2008 a customer wanted to base a product on the Nvidia Tega SoC, so I wrote Nvidia if they could release us any register level spec, even under NDA, to work on such a project. To my surprise I got an answer, but it was a simple one-liner, and not really what we needed to hear:

How is your Windows CE experience? We are not supporting Linux on Tegra.

Received: from hqnvupgp03.nvidia.com (Not Verified[172.17.102.18]) by hqemgate03.nvidia.com
id ; Tue, 22 Jul 2008 12:56:40 -0700
Subject: RE: NVidia SoC SPECs for Embedded Linux systems
Date: Tue, 22 Jul 2008 12:57:03 -0700

How is your Windows CE experience? We are not supporting Linux on Tegra.

—–Original Message—–

For the currently engaging projects we need solid 3D support in
our portfolio we would kindly ask for the possibility to sign an NDA
to receive register level specs support NVidia’s latest integrated
embedded SoC’s in our boards support offerings.

Just for those why I can not, and will never recommend chips without register level data sheets available to developer, ..!