On 08/17/2017 04:07 PM, tedheadster wrote:
Larry, you've migrated a bunch of staging code, and tried various
approaches. Do you have any lessons on what has worked and what hasn't
and if there is anything we can do to make the process better?
I am also quite interested in such work. We asked for a Birds of
Feather discussion at the upcoming Linux Plumbers conference on
exactly this sort of work.
Matthew and Dan,
I will try to answer the question as best I can.
I got started in working with Realtek wireless devices at roughly the time that
staging was created. At that time, Realtek published drivers sporadically. They
would accumulate fixes in their internal svn repositories, then take a snapshot,
and publish that with no information regarding what was changed. Even trying to
diff the two versions was not useful. Obviously this mode of code development is
not consistent with the Linux model.
After I was able to get driver r8712u into staging, I received an E-mail from
Realtek asking if I would be willing to help them get their drivers into the
kernel. They have provided sample chips and extenders to let me test drivers on
my laptops, but I have not gotten any remuneration from Realtek. This
collaboration has led to the rtlwifi family of drivers. A few of them have gone
through staging because there was some urgency in getting them added to Linux.
That is the case for today's submission of a driver for the RTL8822BE, which is
appearing in some computers. This particular device implements a new Realtek
model for hardware abstraction of the MAC, PHY, and dynamic management
functions, which has increased the number of new lines of code to about 120K.
Getting that much new code through the review process in the wireless tree would
take a lot of time. Essentially, staging allows users to have access to the
functionality while that review is in progress. Another card now appearing in
the wild is the RTL8723DE. It will likely also reside initially in staging.
Besides getting wifi drivers for these cards into Linux, I have also been
training the Realtek engineers and getting them to issue fixes as many small
changes. That part of my "job" has been going very well, and I will soon be
getting them to submit their material directly. That change is necessary as I am
now 77, with the question of how long I will be continuing.
As you can tell, I am very pleased with the staging tree and its usage for new
drivers, particularly where the regular trees move more slowly than the
marketplace. Staging is a big help in supporting the users that otherwise will
have no wifi under Linux. Their distro may not build staging drivers in their
standard kernels, but configuring and building kernels is not too difficult.
The part that does not work is best exemplified by the driver that got me
started, namely r8712u. The USB section at Realtek has not been as cooperative
as the PCI/SDIO group. As a result, there is no path from staging to wireless
and that driver will be left in staging as long as GregKH allows it. Now, I put
that sort of material in a GitHub repo and force users to build it as an
out-of-kernel driver. Of course, that method has its own problems. How many
times a week do you want to tell another user that they need to install the
kernel-headers, and no, I do not know how to do it on your distro. Now we have
one example (rtl8723bs) where the GitHub driver was placed in staging. That one
is likely to be moved to wireless.
This reply is getting rather long. I will be happy to answer any further questions.
Larry
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