PCMCIA/CardBus To USB Drivers On The Chopping Block With Linux 6.4

Earlier this month I wrote about Linux 6.4 planning to start removing old, unused, and unmaintained PCMCIA drivers. That began with the PCMCIA "char" drivers queued for removal in this upcoming kernel cycle and now joining them are removing two PCMCIA/CardBus to USB adapter drivers.

Queued up today in Greg's usb-testing branch is set to drop the u132-hcd driver. The driver removal pushed forth by Uwe Kleine-König of Pengutronix explained:

This driver got its last actual change in 2006 and is probably unused as nowbody should use a cardbus to USB adapter any more.

If it were still used, the driver was in urgent need for maintainer love. (Explicit kref handling, underdocumented locking, .remove() can return errors ...)

Also the link in the (now removed) help text doesn't look actively maintained. According to archive.org it forwarded to
[a Copenhagen hotel website] already back in 2018.

So don't waste more time on this driver and just delete it.

This driver was for the Elan U132 adapter host controller for USB to CardBus adapter designed for PC cards with an OHCI host controller, such as some 3G modems.

In addition, the ftdi-elan driver is also called for deletion from the kernel. That removal is summed up as:

This driver didn't see real maintenance since several years. It has several trivial issues (check $(scripts/checkpatch.pl -f drivers/usb/misc/ftdi-elan.c)) and some harder ones (difficult locking, explict kref handling, ...). Also today it's hard to find hardware to make actually use of such a card and I suspect the driver is completely unused.

So remove it.

This driver is for the Elan PCMCIA CardBus Adapter USB Client with the Elan Uxxx series of USB to PCMCIA CardBus adapters. Barring any last minute revival, clearing out these drivers should go in through the USB subsystem pull request for the Linux 6.4 merge window in just over one month's time.

While some like to believe in the possibility for Linux to have an infinite hardware support period, all too often there's very few willing -- and capable -- to commit and step-up to maintain these out-of-date hardware drivers. As such we are going through a purge of seeing unmaintained PCMCIA/CardBus support removed from the mainline kernel. Should anyone be interested in these old drivers, there always is older Linux (LTS) kernel versions to be used or could be easily resurrected in the future thanks to Git if someone wants to step up