The SMBus standard specifies an address resolution protocol (SMBus ARP.) It has two key features :

  • Handle I2C slave address collisions. If two SMBus slaves would use the same I2C address, ARP lets one of them pick a different address to avoid the address collision.
  • Automatically and reliably identify SMBus slaves. Each SMBus slave supporting ARP has a unique device ID, which can be used to automatically instantiate the right I2C device and subsequently let the needed driver be loaded.

Plan

If implemented properly, sensors-detect would no longer be needed on a number of systems, as all required drivers would get loaded automatically.

There has been some work done on SMBus ARP in the past, but nothing good enough to be integrated in the upstream kernel. Mark D. Studebaker wrote proof-of-concept code in 2002, for kernel 2.2. The code was updated for kernel 2.4 but development stopped in 2005.

More recently, Corentin Labbe has been working on proof-of-concept code for kernel 2.6/3. As I recall the code did not actually work, but maybe it can be used as a base.

Results

Miserable failure. Proper hardware support is rare, and prerequisites aren't met.

Looking for hackers with the skills:

kernel hardware

This project is part of:

Hack Week 10

Activity

  • over 8 years ago: zhigangg joined this project.
  • about 11 years ago: jdelvare started this project.
  • about 11 years ago: duwe liked this project.
  • about 11 years ago: wpreston2 liked this project.
  • about 11 years ago: ptesarik liked this project.
  • about 11 years ago: jdelvare added keyword "hardware" to this project.
  • about 11 years ago: jdelvare added keyword "kernel" to this project.
  • about 11 years ago: jdelvare originated this project.

  • Comments

    • jdelvare
      about 11 years ago by jdelvare | Reply

      Things didn't go as good as I hoped. Firstly my own machine no longer replies to the SMBus ARP address, while I'm almost certain it used to. I can't explain it.

      Then I tried to find a machine on the Suse network that would be suitable, but that kind of information doesn't show in orthos, so finding the right machine was difficult. I finally found "knorr", which does reply to the SMBus ARP address, but uses an HT-1000 south bridge for which we don't support SMBus PEC, which is a prerequisite for SMBus ARP. I don't even know if the chipset supports it, and the datasheet is not publicly available.

      So I gave up on "knorr" and now found "fux" which does reply to the SMBus ARP address and uses the i2c-i801 SMBus driver which implements SMBus PEC support. I can start my tests now.

    • jdelvare
      about 11 years ago by jdelvare | Reply

      The curse goes on. "fux" has an ICH10 south bridge, and testing revealed that PEC (CRC) errors during SMBus block transactions (at least) lock up the SMBus controller. I suspect an undocumented erratum. I managed to find a software workaround, I must discuss it with upstream.

      When testing that software workaround on another chip (ICH5) supported by the i2c-i801 driver, I hit another bug related to PEC error handling. I'm still puzzled by that one, I don't understand what is going on and have no idea how to work around it.

      It should be clear by now that I'm not going to complete my hack week project. It turns out that the world is not yet ready for SMBus ARP. First of all we need proper SMBus PEC support on a wide range of machines. Only when this is available, it will make sense to look into SMBus ARP support again.

    Similar Projects

    Create DRM drivers for VESA and EFI framebuffers by tdz

    Description

    We already have simpledrm for firmware framebuffers. But the driver is originally for ARM boards, not PCs. It is already overloaded with code to support both use cases. At the same time it is missing possible features for VESA and EFI, such as palette modes or EDID support. We should have DRM drivers for VESA and EFI interfaces. The infrastructure exists already and initial drivers can be forked from simpledrm.

    Goals

    • Initially, a bare driver for VESA or EFI should be created. It can take functionality from simpledrm.
    • Then we can begin to add additional features. The boot loader can provide EDID data. With VGA hardware, VESA can support paletted modes or color management. Example code exists in vesafb.


    Hacking on sched_ext by flonnegren

    Description

    Sched_ext upstream has some interesting issues open for grabs:

    Goals

    Send patches to sched_ext upstream

    Also set up perfetto to trace some of the example schedulers.

    Resources

    https://github.com/sched-ext/scx


    Model checking the BPF verifier by shunghsiyu

    Project Description

    BPF verifier plays a crucial role in securing the system (though less so now that unprivileged BPF is disabled by default in both upstream and SLES), and bugs in the verifier has lead to privilege escalation vulnerabilities in the past (e.g. CVE-2021-3490).

    One way to check whether the verifer has bugs to use model checking (a formal verification technique), in other words, build a abstract model of how the verifier operates, and then see if certain condition can occur (e.g. incorrect calculation during value tracking of registers) by giving both the model and condition to a solver.

    For the solver I will be using the Z3 SMT solver to do the checking since it provide a Python binding that's relatively easy to use.

    Goal for this Hackweek

    Learn how to use the Z3 Python binding (i.e. Z3Py) to build a model of (part of) the BPF verifier, probably the part that's related to value tracking using tristate numbers (aka tnum), and then check that the algorithm work as intended.

    Resources


    early stage kdump support by mbrugger

    Project Description

    When we experience a early boot crash, we are not able to analyze the kernel dump, as user-space wasn't able to load the crash system. The idea is to make the crash system compiled into the host kernel (think of initramfs) so that we can create a kernel dump really early in the boot process.

    Goal for the Hackweeks

    1. Investigate if this is possible and the implications it would have (done in HW21)
    2. Hack up a PoC (done in HW22 and HW23)
    3. Prepare RFC series (giving it's only one week, we are entering wishful thinking territory here).

    update HW23

    • I was able to include the crash kernel into the kernel Image.
    • I'll need to find a way to load that from init/main.c:start_kernel() probably after kcsan_init()
    • I workaround for a smoke test was to hack kexec_file_load() systemcall which has two problems:
      1. My initramfs in the porduction kernel does not have a new enough kexec version, that's not a blocker but where the week ended
      2. As the crash kernel is part of init.data it will be already stale once I can call kexec_file_load() from user-space.

    The solution is probably to rewrite the POC so that the invocation can be done from init.text (that's my theory) but I'm not sure if I can reuse the kexec infrastructure in the kernel from there, which I rely on heavily.

    update HW24

    • Day1
      • rebased on v6.12 with no problems others then me breaking the config
      • setting up a new compilation and qemu/virtme env
      • getting desperate as nothing works that used to work
    • Day 2
      • getting to call the invocation of loading the early kernel from __init after kcsan_init()
    • Day 3

      • fix problem of memdup not being able to alloc so much memory... use 64K page sizes for now
      • code refactoring
      • I'm now able to load the crash kernel
      • When using virtme I can boot into the crash kernel, also it doesn't boot completely (major milestone!), crash in elfcorehdr_read_notes()
    • Day 4

      • ... more to come (hopefully)
    • Day 5

      • ...

    Resources


    Officially Become a Kernel Hacker! by m.crivellari

    Description

    My studies as well my spare time are dedicated to the Linux Kernel. Currently I'm focusing on interrupts on x86_64, but my interests are not restricted to one specific topic, for now.

    I also "played" a little bit with kernel modules (ie lantern, a toy packet analyzer) and I've added a new syscall in order read from a task A, the memory of a task B.

    Maybe this will be a good chance to...

    Goals

    • create my first kernel patch

    Resources

    Achivements


    Framework laptop integration by nkrapp

    Project Description

    Although openSUSE does run on the Framework laptops out-of-the-box, there is still room to improve the experience. The ultimate goal is to get openSUSE on the list of community supported distros

    Goal for this Hackweek

    The goal this year is to at least package all of the soft- and firmware for accessories like the embedded controller, Framework 16 inputmodule and other tools. I already made some progress by packaging the inputmodule control software, but the firmware is still missing

    Resources

    As I only have a Framework laptop 16 and not a 13 I'm looking for people with hardware that can help me test

    Progress:

    Update 1:

    The project lives under my home for now until I can get an independent project on OBS: Framework Laptop project

    Also, the first package is already done, it's the cli for the led-matrix spacer module on the Framework Laptop 16. I am also testing this myself, but any feedback or questions are welcome.

    You can test the package on the Framework 16 by adding this repo and installing the package inputmodule-control

    Update 2:

    I finished packaging the python cli/gui for the inputmodule. It is using a bit of a hack because one of the dependencies (PySimpleGUI) recently switched to a noncommercial license so I cannot ship it. But now you can actually play the games on the led-matrix (the rust package doesn't include controls for the games). I'm also working on the Framework system tools now, which should be more interesting for Framework 13 users.

    You can test the package on the Framework 16 by installing python311-framework16_inputmodule and then running "ledmatrixctl" from the command line.

    Update 3:

    I packaged the framework_tool, a general application for interacting with the system. You can find it some detailed information what it can do here. On my system everything related to the embedded controller functionality doesn't work though, so some help testing and debugging would be appreciated.

    Update 4:

    Today I finished the qmk interface, which gives your cli (and gui) to configure your Framework 16 keyboard. Sadly the Python gui is broken upstream, but I added the qmk_hid package with the cli and from my testing it works well.


    Capyboard, ESP32 Development Board for Education by emiler

    Description

    Capyboard 3D

    Capyboard is an ESP32 development board built to accept individual custom-made modules. The board is created primarily for use in education, where you want to focus on embedded programming instead of spending time with connecting cables and parts on a breadboard, as you would with Arduino and other such devices. The board is not limited only to education and it can be used to build, for instance, a very powerful internal meteo-station and so on.

    I already have one initial prototype ready and tested. The next iteration addresses several issues the first prototype had. I am planning on finishing up the mainboard and one of the modules this week.

    This project is also a part of my master's thesis.

    Goals

    • Finish testing of a new prototype
    • Publish source files
    • Documentation completion
    • Finish writing thesis

    Resources


    SUSE Prague claw machine by anstalker

    Project Description

    The idea is to build a claw machine similar to e.g. this one:

    example image

    Why? Well, it could be a lot of fun!

    But also it's a great way to dispense SUSE and openSUSE merch like little Geekos at events like conferences, career fairs and open house events.

    Goal for this Hackweek

    Build an arcade claw machine.

    Resources

    In French, an article about why you always lose in claw machine games:

    We're looking for handy/crafty people in the Prague office:

    • woodworking XP or equipment
    • arduino/raspi embedded programming knowledge
    • Anthony can find a budget for going to GM and buying servos and such ;)