Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.
Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.
If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.
If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.
It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When turning class devices into bus devices, we may need to
temporarily add links in sysfs so that user-space applications
are not confused. This is done by adding the following API:
* Functions to register and unregister compatibility classes.
These appear in sysfs at the same location as regular classes, but
instead of class devices, they contain links to bus devices.
* Functions to create and delete such links. Additionally, the caller
can optionally pass a target device to which a "device" link should
point (typically that would be the device's parent), to fully emulate
the original class device.
The i2c subsystem will be the first user of this API, as i2c adapters
are being converted from class devices to bus devices.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Placing dma-coherent.c in driver/base is better than in kernel,
since it contains code to do per-device coherent dma memory
handling.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Let attribute group vectors be declared "const". We'd
like to let most attribute metadata live in read-only
sections... this is a start.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
No one should directly access the driver_data field, so remove the field
and make it private. We dynamically create the private field now if it
is needed, to handle drivers that call get/set before they are
registered with the driver core.
Also update the copyright notices on these files while we are there.
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1271) affects when new devices get linked into their
bus's list of devices. Currently this happens after probing, and it
doesn't happen at all if probing fails. Clearly this is wrong,
because at that point quite a few symbolic links have already been
created in sysfs. We are committed to adding the device, so it should
be linked into the bus's list regardless.
In addition, this needs to happen before the uevent announcing the new
device gets issued. Otherwise user programs might try to access the
device before it has been added to the bus.
To fix both these problems, the patch moves the call to
klist_add_tail() forward from bus_attach_device() to bus_add_device().
Since bus_attach_device() now does nothing but probe for drivers, it
has been renamed to bus_probe_device(). And lastly, the kerneldoc is
updated.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
transition_started should be set once the preparation of devices for
a PM has started, reset before starting to resume devices. When
resuming devices, kernel calls dpm_resume_noirq then
dpm_resume_end(dpm_resume). Thus we should reset transition_started
at dpm_resume_noirq.
This patch fixes ACPI warning when resuming from suspend/hibernate:
ACPI: \_SB_.PCI0.IDE1.PRI1.MAS1 - docking
------------[ cut here ]------------
WARNING: at drivers/base/power/main.c:87 device_pm_add+0x8b/0xcc()
Hardware name: OptiPlex 760
Device: acpi
Parentless device registered during a PM transaction
[rjw: Fixed up the changelog.]
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The kerneldoc comments in drivers/base/power/main.c are generally
outdated and some of them don't describe the functions very
accurately. Update them and standardize the format to use spaces
instead of tabs.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
This patch adds default Runtime PM callbacks to the dev_pm_ops
belonging to the platform bus. The callbacks are weak symbols
that architecture specific code can override.
Allows Runtime PM even though CONFIG_PM_SLEEP=n.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Introduce a core framework for run-time power management of I/O
devices. Add device run-time PM fields to 'struct dev_pm_info'
and device run-time PM callbacks to 'struct dev_pm_ops'. Introduce
a run-time PM workqueue and define some device run-time PM helper
functions at the core level. Document all these things.
Special thanks to Alan Stern for his help with the design and
multiple detailed reviews of the pereceding versions of this patch
and to Magnus Damm for testing feedback.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@igel.co.jp>
Commit 783ea7d4ee
(Driver Core: Rework platform suspend/resume, print warning)
added a warning message printed for platform drivers that use the
legacy PM callbacks rather than struct dev_pm_ops. Unfortunately,
this resulted in some confusion and made some people try to convert
drivers by replacing the old callbacks with struct dev_pm_ops in
automatic way, which generally is not a good idea.
Remove the platform device runtime dev_pm_ops warning for now,
because it's annoying to users and it's not really necessary right
now.
[rjw: Modified the changelog to be more informative.]
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
If kobject_init_and_add fails, sysdev_register should not send KOBJ_ADD
uevent to userspace.
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The page pointers array is allocated in fw_realloc_buffer() called by
firmware_data_write(), and should be freed in release function of firmware
device.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They are not supposed to be modified by drivers, so make them const.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This is V2 of the platform driver power management late/early
callback removal patch. The callbacks ->suspend_late() and
->resume_early() are removed since all in-tree users now have
been migrated to dev_pm_ops.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
I just debugged an obscure crash caused by a device_del() of a all NULL'd
out struct device (in usb-serial) and found that a patch like this one would
have saved me time (in addition to improved chances of a bug report from
users hitting similar driver bugs).
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
PM: Clear -EAGAIN in dpm_prepare
x86: Fix resume from suspend when CONFIG_CC_STACKPROTECTOR
The f_dev in _request_firmware() is allocated via the fw_setup_device()
and fw_register_device() calls and its class set to firmware_class (the
class release function is fw_dev_release).
Commit 6acf70f078 replaced the kfree(dev) in fw_dev_release() with a
put_device() call but my understanding is that the release function is
called via put_device -> kobject_put -> kref_put -> koject_release etc.
and it should call kfree since it's the last to see this device
structure alive.
Because of that, the _request_firmware() function on its -ENOENT error
path only calls device_unregister(f_dev) which would eventually call
fw_dev_release() but there is no kfree (the subsequent put_device call
would just make the kref negative).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the last device in the dpm list is unregistered directly after its
prepare() callback returned with -EAGAIN, the return code is passed to
the calling function, resulting in a suspend failure. Prevent this by
clearing the return code after -EAGAIN.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* akpm: (182 commits)
fbdev: bf54x-lq043fb: use kzalloc over kmalloc/memset
fbdev: *bfin*: fix __dev{init,exit} markings
fbdev: *bfin*: drop unnecessary calls to memset
fbdev: bfin-t350mcqb-fb: drop unused local variables
fbdev: blackfin has __raw I/O accessors, so use them in fb.h
fbdev: s1d13xxxfb: add accelerated bitblt functions
tcx: use standard fields for framebuffer physical address and length
fbdev: add support for handoff from firmware to hw framebuffers
intelfb: fix a bug when changing video timing
fbdev: use framebuffer_release() for freeing fb_info structures
radeon: P2G2CLK_ALWAYS_ONb tested twice, should 2nd be P2G2CLK_DAC_ALWAYS_ONb?
s3c-fb: CPUFREQ frequency scaling support
s3c-fb: fix resource releasing on error during probing
carminefb: fix possible access beyond end of carmine_modedb[]
acornfb: remove fb_mmap function
mb862xxfb: use CONFIG_OF instead of CONFIG_PPC_OF
mb862xxfb: restrict compliation of platform driver to PPC
Samsung SoC Framebuffer driver: add Alpha Channel support
atmel-lcdc: fix pixclock upper bound detection
offb: use framebuffer_alloc() to allocate fb_info struct
...
Manually fix up conflicts due to kmemcheck in mm/slab.c
Kay Sievers
Andrew Morton
Jean Delvare
Ming Lei
David Brownell
Greg Kroah-Hartman
Alan Stern
Xiaotian Feng
Rafael J. Wysocki
Magnus Damm
Dmitry Torokhov
Jiri Slaby
Benjamin Herrenschmidt
Linus Torvalds
Catalin Marinas
Sebastian Ott
KOSAKI Motohiro