kernel/git/stable/linux.git/drivers/isdn/capi/Kconfig, branch master

net: remove ISDN subsystem and Bluetooth CMTP

2026-04-23T17:24:02+00:00

Remove the ISDN (mISDN, CAPI) subsystem and Bluetooth CMTP protocol from the kernel tree. ISDN is a pretty old technology and it's unclear whether anyone still uses it. I went over the last few years of git history and all the commits are either tree-wide conversions or syzbot/static analyzer fixes. When we discussed removal in the past IIRC there were some concerns about ISDN still being used in parts of Germany. Unfortunately, the code base is quite old, none of the current maintainers are familiar with it and AI tools will have a field day finding bugs here. Delete this code and preserve it in an out-of-tree repository for any remaining users: https://github.com/linux-netdev/mod-orphan UAPI constants AF_ISDN/PF_ISDN and the SELinux isdn_socket class are preserved for ABI stability, but the rest of uAPI is removed. Signed-off-by: Jakub Kicinski Acked-by: Greg Kroah-Hartman Acked-by: Stephen Hemminger Acked-by: Luiz Augusto von Dentz Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260421022108.1299678-1-kuba@kernel.org Signed-off-by: Paolo Abeni

isdn/capi: Replace HTTP links with HTTPS ones

2020-07-14T00:25:35+00:00

Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Deterministic algorithm: For each file: If not .svg: For each line: If doesn't contain `\bxmlns\b`: For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`: If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`: If both the HTTP and HTTPS versions return 200 OK and serve the same content: Replace HTTP with HTTPS. Signed-off-by: Alexander A. Klimov Signed-off-by: David S. Miller

isdn: capi: dead code removal

2019-12-11T08:12:38+00:00

The staging isdn drivers are gone, and CONFIG_BT_CMTP is now the only user. This means a lot of the code in the subsystem has no remaining callers and can be removed. Change the capi user space front-end to be part of kernelcapi, and the combined module to only be compiled if BT_CMTP is also enabled, then remove the interfaces that have no remaining callers. As the notifier list and the capi_drivers list have no callers outside of kcapi.c, the implementation gets much simpler. Some definitions from the include/linux/*.h headers are only needed internally and are moved to kcapi.h. Acked-by: David Miller Signed-off-by: Arnd Bergmann Link: https://lore.kernel.org/r/20191210210455.3475361-2-arnd@arndb.de Signed-off-by: Greg Kroah-Hartman

isdn: move capi drivers to staging

2019-05-31T09:17:41+00:00

I tried to find any indication of whether the capi drivers are still in use, and have not found anything from a long time ago. With public ISDN networks almost completely shut down over the past 12 months, there is very little you can actually do with this hardware. The main remaining use case would be to connect ISDN voice phones to an in-house installation with Asterisk or LCR, but anyone trying this in turn seems to be using either the mISDN driver stack, or out-of-tree drivers from the hardware vendors. I may of course have missed something, so I would suggest moving these three drivers (avm, hysdn, gigaset) into drivers/staging/ just in case someone still uses them. If nobody complains, we can remove them entirely in six months, or otherwise move the core code and any drivers that are still needed back into drivers/isdn. As Paul Bolle notes, he is still testing the gigaset driver as long as he can, but the Dutch ISDN network will be shut down in September 2019, which puts an end to that. Marcel Holtmann still maintains the Bluetooth CMTP profile and wants to keep that alive, so the actual CAPI subsystem code remains in place for now, after all other drivers are gone, CMTP and CAPI can be merged into a single driver directory. Cc: Marcel Holtmann Cc: Paul Bolle Signed-off-by: Arnd Bergmann

isdn: remove isdn4linux

2019-05-31T09:13:10+00:00

With all isdn4linux hardware drivers gone, this is only a wrapper around CAPI to support old user space. However, from looking at the mailing list, it seems that the last time anyone asked about it was in 2014, when the upgrade from a linux-2.4 installation failed, and mISDN was suggested as a replacement. The largest public ISDN network (Deutsche Telekom) was supposed to be shut down 2018, which must have drastically reduced the number of legacy installations. When we last discussed removing i4l in 2016, Karsten Keil suggested revisiting this in 2018. I guess this is overdue. Link: http://listserv.isdn4linux.de/pipermail/isdn4linux/2014-October/006165.html Link: https://patchwork.kernel.org/patch/8484861/#17900371 Link: https://listserv.isdn4linux.de/pipermail/isdn4linux/2019-April/thread.html Signed-off-by: Arnd Bergmann

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

isdn/capi: fix (middleware) device nodes

2014-06-05T06:13:41+00:00

Since v2.4 the capi driver used the following device nodes if "middleware" support was enabled: /dev/capi20 /dev/capi/0 /dev/capi/1 [...] /dev/capi20 is a character device node. /dev/capi/0 (and up) are tty device nodes (with a different major). This device node (naming) scheme is not documented anywhere, as far as I know. It was originally provided by the capifs pseudo filesystem (before udev became available). It is required for example by the pppd capiplugin. It was supported until a few years ago. But a number of developments broke it: - v2.6.6 (May 2004) renamed /dev/capi20 to /dev/capi and removed the "/" from the name of capi's tty driver. The explanation of the patch that did this included two examples of udev rules "to restore the old namespace"; - either udev 154 (May 2010) or udev 179 (January 2012) stopped allowing to rename device nodes, and thus the ability to have /dev/capi20 appear instead of /dev/capi and /dev/capi/0 (and up) instead of /dev/capi0 (and up); - v3.0 (July 2011) also removed capifs. That disabled another method to create the /dev/capi/0 (and up) device nodes. So now users need to manually tweak their setup (eg, create /dev/capi/ and fill that with symlinks) to get things working. This is all rather hacky and only discoverable by searching the web. Fix all this by renaming /dev/capi back to /dev/capi20, and by setting the name of the "capi_nc" tty driver to "capi!" so the tty device nodes appear as /dev/capi/0 (and up). Signed-off-by: Paul Bolle Signed-off-by: Tilman Schmidt Acked-by: Greg Kroah-Hartman Signed-off-by: David S. Miller

isdn/capi: Make verbose reporting depend on capidrv

2014-06-05T06:13:41+00:00

The Kconfig symbol ISDN_DRV_AVMB1_VERBOSE_REASON is only used for capi_info2str(). That function is only used in capidrv.c. So setting it without setting ISDN_CAPI_CAPIDRV is pointless. Make it depend on ISDN_CAPI_CAPIDRV, rename it to ISDN_CAPI_CAPIDRV_VERBOSE and put its entry after ISDN_CAPI_CAPIDRV's entry. Since this symbol seems to be primarily used for debugging, keep it off by default. By now the last users of capidrv hopefully know all they need to know about the reasons for disconnecting. Signed-off-by: Paul Bolle Signed-off-by: Tilman Schmidt Signed-off-by: David S. Miller

isdn/capi: Make Middleware depend on CAPI2.0

2014-03-18T19:02:57+00:00

The Kconfig symbol ISDN_CAPI_MIDDLEWARE is only used in capi.c. Setting it without setting ISDN_CAPI_CAPI20 is therefor useless. Make it depend on ISDN_CAPI_CAPI20 and put its entry after ISDN_CAPI_CAPI20's entry. Signed-off-by: Paul Bolle Signed-off-by: Tilman Schmidt Signed-off-by: David S. Miller

tty: Added a CONFIG_TTY option to allow removal of TTY

2013-01-19T00:15:27+00:00

The option allows you to remove TTY and compile without errors. This saves space on systems that won't support TTY interfaces anyway. bloat-o-meter output is below. The bulk of this patch consists of Kconfig changes adding "depends on TTY" to various serial devices and similar drivers that require the TTY layer. Ideally, these dependencies would occur on a common intermediate symbol such as SERIO, but most drivers "select SERIO" rather than "depends on SERIO", and "select" does not respect dependencies. bloat-o-meter output comparing our previous minimal to new minimal by removing TTY. The list is filtered to not show removed entries with awk '$3 != "-"' as the list was very long. add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350) function old new delta chr_dev_init 166 170 +4 allow_signal 80 82 +2 static.__warned 143 142 -1 disallow_signal 63 62 -1 __set_special_pids 95 94 -1 unregister_console 126 121 -5 start_kernel 546 541 -5 register_console 593 588 -5 copy_from_user 45 40 -5 sys_setsid 128 120 -8 sys_vhangup 32 19 -13 do_exit 1543 1526 -17 bitmap_zero 60 40 -20 arch_local_irq_save 137 117 -20 release_task 674 652 -22 static.spin_unlock_irqrestore 308 260 -48 Signed-off-by: Joe Millenbach Reviewed-by: Jamey Sharp Reviewed-by: Josh Triplett Signed-off-by: Greg Kroah-Hartman