Hauke, Johannes, or any other backports users/developers,
I recently spoke to Luis Chamberlain about a few different things
related my new shared maintainership of rtw,rtl drivers on GitHub that
are under Larry Finger's account:
https://github.com/lwfinger?tab=repositories
The main thing I wanted to discuss is related to the sustainability,
longevity, and utility of maintaining a few in-tree, standalone manual
(#if #else #endif) backports for realtek:
https://github.com/lwfinger/rtw88
https://github.com/lwfinger/rtw89
If you want to see where Larry introduces me, it's here:
https://github.com/lwfinger/rtw88/issues/151#issuecomment-1604503581
I just wanted to reach out about these repos and the options and
tradeoffs with porting them over to the backports.git project in a way
that will benefit the larger community and our existing users.
I am able to begin the work on these drivers if we decide to try and
merge them into backports.git, but I need to understand a few things
since my understanding is often the biggest limitation in all of this.
On more than one occasion, I have gotten confused about how Linux
backports does things so I want to make sure I am making the right
assumptions about how it works with respect to commit history and a few
other things for their respective drivers.
My current understanding re: commit history is as follows:
The main Linux backports project does not preserve the commit history of
individual drivers as they exist in their original trees that they are
taken from. The main goal of the backports project is taking code from
newer Linux kernel versions and adapting them so they can be compiled
and run on older kernel versions. This backporting process is automated
by applying a series of patches to make the newer code compatible with
the older kernel via automation defined in the backports.git repo
through Makefile, Kconfig, dependent .c or .h files, etc. and of course
the "semantic patch language" scripts of coccinelle.
Because the goal is to make new code work with old kernels, rather than
to maintain a faithful, version-controlled history of that code, the
commit history for individual drivers is not included in project's
focus. The version control history in the backports.git repository
serves to track changes to the backporting process itself, rather than
to preserve the history of the backported code (I know that may be
obvious, but I need to make sure I am not mistaken.)
In a nutshell, the Linux backports project is geared towards
compatibility and functionality, not towards historical preservation of
codebase evolution.
The second thing I want to make sure I understand is how users can get
backports for a driver via the Linux backports project:
A happy path would look like them pulling down a tar of backports for
their kernel version from
https://cdn.kernel.org/pub/linux/kernel/projects/backports/stable/ and
then running something like:
```sh
# as a user
make defconfig-rtlwifi
make -j4
# as root
make install
# reboot and enjoy
```
If a feature they need is not in a stable version, they will then have
to execute a small series of extra steps to compile their own backports
release and then use that; whether it's against linux-next or some other
tree. This is a documented and relatively well-traveled path in kernel
developer terms, but is likely out of reach for many "regular" users. I
think it is fair to say that this would require them to be a closer to a
"developer" or experienced Linux user or administrator. They also may
not know about or be able to find the docs for doing so. A GitHub repo
with their device driver name is often what they find first.
The last thing I want to make sure I have straight is the value of
backports.git for wireless drivers generally because there seem to be many:
For maintainers/developers, backports.git offers a standardized,
automated system that minimizes errors, streamlines many aspects of
building, testing, and iterating, and allows for community-vetted (more
eyes), secure code. This centralization frees maintainers to focus on
other development priorities like fixing/reproducing bugs and landing
patches upstream.
For users, backports.git provides a stable way to access these new
features and fixes. It also can be quite simple if you have the right
kernel version, it lines up with the feature you need, or you have the
requisite experience and can find then dive into more "developer-like"
documentation.
For the community, integrating the drivers into backports.git holds
benefits for downstream projects like OpenWrt, which already rely on
backports as a core design feature. Therefore OpenWrt and similar
projects can more seamlessly and securely include them in their
distributions, enhancing both device support and the end-user
experience. In addition, the upstream drivers benefit due to increased
visibility and accessibility, encouraging wider community engagement for
testing, bug reporting, and code contributions.
This approach serves to unify efforts, improve security, and facilitate
a solid, shared pipeline for maintainers, users, and the larger community.
In conclusion, there are a few questions I am trying to answer for
myself, but could use any feedback on.
1. How critical is the preservation of commit history for effective
debugging and bisecting when issues arise in the backported drivers? We
have the commit history in our GitHub repos, but they would not be
present in drivers compiled from backports.git. Is there a way to have
"the best of both worlds" or mitigate the effects of lacking that history?
2. Are there methods to automate or simplify the process for users who
need features not yet available in stable releases, to reduce the skill
barrier?
3. How can I help the backports project directly (rtw related or not)?
4. How can we best leverage the years of effort and modifications (#if
#else #endif macros) made by Larry in these stand-alone repositories to
inform the technical work of porting them to the shared backports framework?
5. Given the popularity and visibility of the rtw88 and rtw89 GitHub
repositories, as indicated by their star counts, issue activity, and
search engine ranking, what strategies can we employ to maintain this
level of user engagement and support if we transition to backports.git?
Would mirroring the code and providing custom-tailored instructions in
the READMEs serve dual purposes of user support and elevating the
visibility of backports.git in the larger community? Is this a welcomed
proposition?
I understand that many of these questions ultimately require hands-on
work and investigation on my part. However, I believe now is an
opportune time to engage the community in these discussions.
I will be attending the Linux Plumbers Conference next month on behalf
of Larry and myself and would like to use this as a start to further
explore potential collaborations and conversations around these topics.
Lastly, I want to thank the backports.git maintainers for providing an
invaluable tool for the Linux community. Also, thank you Luis for
getting me started on having these conversations.
Thank you for your time, and I look forward to future discussions.
Thanks,
Brian Witte
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