On Mon, Feb 27, 2023, at 20:07, Oliver Hartkopp wrote:

Hello Arnd,

On 27.02.23 14:34, Arnd Bergmann wrote:

quoted

From: Arnd Bergmann <arnd@arndb.de>

(..)

quoted

The remaining cardbus/yenta support is essentially a PCI hotplug driver
with a slightly unusual sysfs interface, and it would still support all
32-bit cardbus hosts and cards, but no longer work with the even older
16-bit cards that require the pcmcia_driver infrastructure.

I'm using a 2005 Samsung X20 laptop (Pentium M 1.6GHz, Centrino) with 
PCMCIA (type 2) CAN bus cards:

- EMS PCMCIA
https://elixir.bootlin.com/linux/latest/source/drivers/net/can/sja1000/ems_pcmcia.c

- PEAK PCCard
https://elixir.bootlin.com/linux/latest/source/drivers/net/can/sja1000/peak_pcmcia.c

As I still maintain the EMS PCMCIA and had to tweak and test a patch 
recently (with a 5.16-rc2 kernel):

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/can/sja1000/ems_pcmcia.c?id=3ec6ca6b1a8e64389f0212b5a1b0f6fed1909e45

I assume these CAN bus PCMCIA interfaces won't work after your patch 
set, right?

Correct, the patch series in its current form breaks this since
your laptop is cardbus compatible. The options I can see are:

- abandon my series and keep everything unchanged, possibly removing
  some of the pcmcia drivers that Dominik identified as candidates

- decide on a future timeline for when you are comfortable with
  discontinuing this setup and require any CAN users with cardbus
  laptops to move to USB or cardbus CAN adapters, apply the series
  then

- duplicate the yenta_socket driver to have two variants of that,
  require the user to choose between the cardbus and the pcmcia
  variant depending on what card is going to be used.

Can you give more background on who is using the EMS PCMCIA card?
I.e. are there reasons to use this device on modern kernels with
machines that could also support the USB, expresscard or cardbus
variants, or are you likely the only one doing this for the
purpose of maintaining the driver?

      Arnd