History log of /linux-master/Documentation/admin-guide/devices.txt
Revision Date Author Comments
# 0be916a6 16-Nov-2023 Manikanta Guntupalli <manikanta.guntupalli@amd.com>

Documentation: devices.txt: Update ttyUL major number allocation details

Describe when uartlite driver uses static/dynamic allocation for major
number based on maximum number of uartlite serial ports.

Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
Link: https://lore.kernel.org/r/20231116134003.3762725-2-manikanta.guntupalli@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# 4b91dcc2 14-Aug-2023 Christophe Leroy <christophe.leroy@csgroup.eu>

Documentation: devices.txt: Fix minors for ttyCPM*

ttyCPM* devices belong to CPM_UART driver at the first place
and that driver provides 6 ports.

Fixes: e29c3f81eb89 ("Documentation: devices.txt: reconcile serial/ucc_uart minor numers")
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/27d7124cf86157e2a27c2b039e769041994d3f22.1691992627.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# 27681960 14-Aug-2023 Christophe Leroy <christophe.leroy@csgroup.eu>

Documentation: devices.txt: Remove ttySIOC*

IOC3 serial driver was removed, remove associated devices
from documentation.

Fixes: 9c860e4cf708 ("tty/serial: remove the ioc3_serial driver")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/f13b5c64f8cb6d8f2357d7be14397676b27ac2a2.1691992627.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# e327fdc2 14-Aug-2023 Christophe Leroy <christophe.leroy@csgroup.eu>

Documentation: devices.txt: Remove ttyIOC*

IOC4 serial driver was removed, remove associated devices
from documentation.

Fixes: a017ef17cfd8 ("tty/serial: remove the ioc4_serial driver")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/b5deb1222eb92017f0efe5b5cae127ac11983b3d.1691992627.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# e29c3f81 24-Jul-2023 Randy Dunlap <rdunlap@infradead.org>

Documentation: devices.txt: reconcile serial/ucc_uart minor numers

Reconcile devices.txt with serial/ucc_uart.c regarding device number
assignments. ucc_uart.c supports 4 ports and uses minor devnums
46-49, so update devices.txt with that info.
Then update ucc_uart.c's reference to the location of the devices.txt
list in the kernel source tree.

Fixes: d7584ed2b994 ("[POWERPC] qe-uart: add support for Freescale QUICCEngine UART")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Timur Tabi <timur@kernel.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: linux-serial@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/20230724063341.28198-1-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# 8bf48897 31-Oct-2022 Oded Gabbay <ogabbay@kernel.org>

drivers/accel: define kconfig and register a new major

Add a new Kconfig for the accel subsystem. The Kconfig currently
contains only the basic CONFIG_DRM_ACCEL option that will be used to
decide whether to compile the accel registration code. Therefore, the
kconfig option is defined as bool.

The accel code will be compiled as part of drm.ko and will be called
directly from the DRM core code. The reason we compile it as part of
drm.ko and not as a separate module is because of cyclic dependency
between drm.ko and the separate module (if it would have existed).
This is due to the fact that DRM core code calls accel functions and
vice-versa.

The accelerator devices will be exposed to the user space with a new,
dedicated major number - 261.

The accel init function registers the new major number as a char device
and create corresponding sysfs and debugfs root entries, similar to
what is done in DRM init function.

I added a new header called drm_accel.h to include/drm/, that will hold
the prototypes of the drm_accel.c functions. In case CONFIG_DRM_ACCEL
is set to 'N', that header will contain empty inline implementations of
those functions, to allow DRM core code to compile successfully
without dependency on CONFIG_DRM_ACCEL.

I Updated the MAINTAINERS file accordingly with the newly added folder
and I have taken the liberty to appropriate the dri-devel mailing list
and the dri-devel IRC channel for the accel subsystem.

Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Tested-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>


# 89fbca33 26-Apr-2022 Jakub Kicinski <kuba@kernel.org>

net: wan: remove support for COSA and SRP synchronous serial boards

Looks like all the changes to this driver had been automated
churn since git era begun. The driver is using virt_to_bus()
so it should be updated to a proper DMA API or removed. Given
the latest "news" entry on the website is from 1999 I'm opting
for the latter.

I'm marking the allocated char device major number as [REMOVED],
I reckon we can't reuse it in case some SW out there assumes its
COSA?

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>


# 473dcf0f 16-Dec-2021 Alexandre Ghiti <alexandre.ghiti@canonical.com>

Documentation, arch: Remove leftovers from raw device

Raw device interface was removed so remove all references to configs
related to it.

Fixes: 603e4922f1c8 ("remove the raw driver")
Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Acked-by: Arnd Bergmann <arnd@arndb.de> [arch/arm/configs]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>


# 8d7e415d 28-Jul-2021 Leon Romanovsky <leon@kernel.org>

docs: Fix infiniband uverbs minor number

Starting from the beginning of infiniband subsystem, the uverbs char
devices start from 192 as a minor number, see
commit bc38a6abdd5a ("[PATCH] IB uverbs: core implementation").

This patch updates the admin guide documentation to reflect it.

Fixes: 9d85025b0418 ("docs-rst: create an user's manual book")
Link: https://lore.kernel.org/r/bad03e6bcde45550c01e12908a6fe7dfa4770703.1627477347.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>


# bbcd53c9 06-May-2021 David Hildenbrand <david@redhat.com>

drivers/char: remove /dev/kmem for good

Patch series "drivers/char: remove /dev/kmem for good".

Exploring /dev/kmem and /dev/mem in the context of memory hot(un)plug and
memory ballooning, I started questioning the existence of /dev/kmem.

Comparing it with the /proc/kcore implementation, it does not seem to be
able to deal with things like

a) Pages unmapped from the direct mapping (e.g., to be used by secretmem)
-> kern_addr_valid(). virt_addr_valid() is not sufficient.

b) Special cases like gart aperture memory that is not to be touched
-> mem_pfn_is_ram()

Unless I am missing something, it's at least broken in some cases and might
fault/crash the machine.

Looks like its existence has been questioned before in 2005 and 2010 [1],
after ~11 additional years, it might make sense to revive the discussion.

CONFIG_DEVKMEM is only enabled in a single defconfig (on purpose or by
mistake?). All distributions disable it: in Ubuntu it has been disabled
for more than 10 years, in Debian since 2.6.31, in Fedora at least
starting with FC3, in RHEL starting with RHEL4, in SUSE starting from
15sp2, and OpenSUSE has it disabled as well.

1) /dev/kmem was popular for rootkits [2] before it got disabled
basically everywhere. Ubuntu documents [3] "There is no modern user of
/dev/kmem any more beyond attackers using it to load kernel rootkits.".
RHEL documents in a BZ [5] "it served no practical purpose other than to
serve as a potential security problem or to enable binary module drivers
to access structures/functions they shouldn't be touching"

2) /proc/kcore is a decent interface to have a controlled way to read
kernel memory for debugging puposes. (will need some extensions to
deal with memory offlining/unplug, memory ballooning, and poisoned
pages, though)

3) It might be useful for corner case debugging [1]. KDB/KGDB might be a
better fit, especially, to write random memory; harder to shoot
yourself into the foot.

4) "Kernel Memory Editor" [4] hasn't seen any updates since 2000 and seems
to be incompatible with 64bit [1]. For educational purposes,
/proc/kcore might be used to monitor value updates -- or older
kernels can be used.

5) It's broken on arm64, and therefore, completely disabled there.

Looks like it's essentially unused and has been replaced by better
suited interfaces for individual tasks (/proc/kcore, KDB/KGDB). Let's
just remove it.

[1] https://lwn.net/Articles/147901/
[2] https://www.linuxjournal.com/article/10505
[3] https://wiki.ubuntu.com/Security/Features#A.2Fdev.2Fkmem_disabled
[4] https://sourceforge.net/projects/kme/
[5] https://bugzilla.redhat.com/show_bug.cgi?id=154796

Link: https://lkml.kernel.org/r/20210324102351.6932-1-david@redhat.com
Link: https://lkml.kernel.org/r/20210324102351.6932-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Alexander A. Klimov" <grandmaster@al2klimov.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Andrey Zhizhikin <andrey.zhizhikin@leica-geosystems.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: Corentin Labbe <clabbe@baylibre.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Gregory Clement <gregory.clement@bootlin.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hillf Danton <hdanton@sina.com>
Cc: huang ying <huang.ying.caritas@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: James Troup <james.troup@canonical.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kairui Song <kasong@redhat.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: openrisc@lists.librecores.org
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Pavel Machek (CIP)" <pavel@denx.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Pierre Morel <pmorel@linux.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: sparclinux@vger.kernel.org
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Theodore Dubois <tblodt@icloud.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: William Cohen <wcohen@redhat.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>


# 67b1544a 01-Mar-2021 Jiri Slaby <jirislaby@kernel.org>

tty: isicom, remove this orphan

The Isicom driver was orphaned by commit d86b3001a1a6 (MAINTAINERS:
orphan isicom) 10 years ago. Noone stepped up to take care of them and
to fix all the issues the driver has.

So it's time to drop the driver with all its traces.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-6-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# f76edd8f 01-Mar-2021 Jiri Slaby <jirislaby@kernel.org>

tty: cyclades, remove this orphan

The Cyclades driver was orphaned by commit d459883e6c54 (MAINTAINERS:
remove two dead e-mail) 13 years ago. Noone stepped up to take care of
them and to fix all the issues the driver has.

On the top of that, there is no way to obtain the firmware for Z cards
from the vendor as cyclades.com ceased to exist.

So it's time to drop the driver with all its traces.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210302062214.29627-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# 15ab8569 16-Aug-2020 Theodore Dubois <tblodt@icloud.com>

devices.txt: fix typo of "ubd" as "udb"

Signed-off-by: Theodore Dubois <tblodt@icloud.com>
Link: https://lore.kernel.org/r/20200816233823.86316-1-tblodt@icloud.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>


# 5569f896 26-Jul-2020 Pavel Machek <pavel@ucw.cz>

devices.txt: document rfkill allocation

Document rfkill allocation.

Signed-off-by: Pavel Machek (CIP) <pavel@denx.de>

Link: https://lore.kernel.org/r/20200726075327.GA25647@duo.ucw.cz
Signed-off-by: Jonathan Corbet <corbet@lwn.net>


# 6b2484e1 27-Jun-2020 Alexander A. Klimov <grandmaster@al2klimov.de>

Replace HTTP links with HTTPS ones: Documentation/admin-guide

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 both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200627072935.62652-1-grandmaster@al2klimov.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>


# fb0c90ab 09-Jan-2020 Jacob Keller <jacob.e.keller@intel.com>

doc: fix typo of snapshot in documentation

A couple of locations accidentally misspelled snapshot as shapshot.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>


# 19a602b7 10-Jan-2020 Colin Ian King <colin.king@canonical.com>

devices.txt: fix spelling mistake: "shapshot" -> "snapshot"

Fix spelling mistake in text.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20200110100427.236530-1-colin.king@canonical.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>


# d62e8055 11-Sep-2019 Ian Abbott <abbotti@mev.co.uk>

devices.txt: improve entry for comedi (char major 98)

Describe how the comedi minor device numbers are split across comedi
devices and comedi subdevices.

Replace the current, long dead URL with an official URL for the Comedi
project.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>


# ecd6bf67 26-Jun-2019 Mark Greer <mgreer@animalcreek.com>

serial: mpsc: Remove obsolete MPSC driver

Support for the Marvell MV64x60 line of bridge chips that contained
MPSC controllers has been removed and there are no other components
that have that controller so remove its driver.

Signed-off-by: Mark Greer <mgreer@animalcreek.com>
Link: https://lore.kernel.org/r/20190626160553.28518-1-mgreer@animalcreek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# 13aa0a12 17-Jul-2018 Nicolas Pitre <nico@fluxnic.net>

vt: add /dev/vcsu* to devices.txt

Also mention that the traditional devices provide glyph values whereas
/dev/vcsu* is unicode based.

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# a5d31a3f 15-Jun-2017 Logan Gunthorpe <logang@deltatee.com>

char_dev: extend dynamic allocation of majors into a higher range

We've run into problems with running out of dynamicly assign char
device majors particullarly on automated test systems with
all-yes-configs. Roughly 40 dynamic assignments can be made with such
kernels at this time while space is reserved for only 20.

Currently, the kernel only prints a warning when dynamic allocation
overflows the reserved region. And when this happens drivers that have
fixed assignments can randomly fail depending on the order of
initialization of other drivers. Thus, adding a new char device can cause
unexpected failures in completely unrelated parts of the kernel.

This patch solves the problem by extending dynamic major number
allocations down from 511 once the 234-254 region fills up. Fixed
majors already exist above 255 so the infrastructure to support
high number majors is already in place. The patch reserves an
additional 128 major numbers which should hopefully last us a while.

Kernels that don't require more than 20 dynamic majors assigned (which
is pretty typical) should not be affected by this change.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Link: https://lkml.org/lkml/2017/6/4/107
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# f4660cc9 10-May-2017 Stefan Hajnoczi <stefanha@redhat.com>

vhost/vsock: use static minor number

Vhost-vsock is a software device so there is no probe call that causes
the driver to register its misc char device node. This creates a
chicken and egg problem: userspace applications must open
/dev/vhost-vsock to use the driver but the file doesn't exist until the
kernel module has been loaded.

Use the devname modalias mechanism so that /dev/vhost-vsock is created
at boot. The vhost_vsock kernel module is automatically loaded when the
first application opens /dev/host-vsock.

Note that the "reserved for local use" range in
Documentation/admin-guide/devices.txt is incorrect. The userio driver
already occupies part of that range. I've updated the documentation
accordingly.

Cc: device@lanana.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


# 07c7e30c 02-Nov-2016 Jani Nikula <jani.nikula@intel.com>

Documentation/admin-guide: split the device list to a separate file

Include the literal device list from a separate file. This helps the pdf
build.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>