Linux 7.2 is continuing the trend of removing obsolete hardware drivers for which the code hasn't seen any maintenance in years and there are no believed users left of said drivers, especially those that would be running modern mainline versions of the Linux kernel. The char/misc changes merged dropped two more obsolete drivers from the Linux source tree.

First up is the removal of the DTLK driver, which was touched on last month on Phoronix. The DTLK driver is a ISA speech synthesizer driver that upstream developers believe likely hasn't been used in decades. After all, it's ISA-based... Plus the hardware can be supported by the alternative Speakup driver for screen reader use. Besides no active end-users, the driver hasn't seen any real changes in the entire history of Linux kernel Git usage beyond the typical tree-wide clean-ups. So it's let go.

The other driver nuked in Linux 7.2 is the Applicom Profibus driver. PROFIBUS is the Process Field Bus as a digital communication protocol commonly used for industrial automation. The Applicom Profibus driver being removed, the "applicom" char driver, was used for their PCI-based driver. This applicom driver was derived from the SCO Unix driver in 1998. This driver hasn't seen much activity since the Linux 2.1~2.2 days.

The patch removing the Applicom driver describes it as a low-quality, unused driver and adds:

"The applicom driver supports PCI Profibus cards from Applicom, later acquired by Molex. It has severe coding style issues and has attracted a number of bug and security fixes over the years, despite the fact that no one appears to be using it. It was broken from at least the beginning of Git history (Linux 2.6.12-rc2 in April 2005) until October 2008, when a fatal bug was fixed in commit bc20589bf1c6 ("applicom.c: fix apparently-broken code in do_ac_read()"). In the commit message, the author commented that no one they knew was able to test the change. Since then, there have been no commits that indicate the driver is being used. Later PCI and PCI-Express Applicom Profibus cards only officially support Windows, and even the PCI-Express cards have been discontinued. Given all these factors, remove the driver to reduce future maintenance workload."

With the successful merge of the char/misc pull, the DTLK and Applicom drivers have been removed from Linux 7.2. These removals yielded the char/misc pull dropping 19.5k lines of code while adding only 8.2k lines.