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  1. 27 7月, 2013 2 次提交
  3. 17 7月, 2013 2 次提交
  5. 04 6月, 2013 1 次提交
  7. 22 5月, 2013 2 次提交
  9. 12 5月, 2013 1 次提交
    • R
      Driver core: Add offline/online device operations · 4f3549d7
      由 Rafael J. Wysocki 提交于 
      In some cases, graceful hot-removal of devices is not possible,
although in principle the devices in question support hotplug.
For example, that may happen for the last CPU in the system or
for memory modules holding kernel memory.

In those cases it is nice to be able to check if the given device
can be gracefully hot-removed before triggering a removal procedure
that cannot be aborted or reversed.  Unfortunately, however, the
kernel currently doesn't provide any support for that.

To address that deficiency, introduce support for offline and
online operations that can be performed on devices, respectively,
before a hot-removal and in case when it is necessary (or convenient)
to put a device back online after a successful offline (that has not
been followed by removal).  The idea is that the offline will fail
whenever the given device cannot be gracefully removed from the
system and it will not be allowed to use the device after a
successful offline (until a subsequent online) in analogy with the
existing CPU offline/online mechanism.

For now, the offline and online operations are introduced at the
bus type level, as that should be sufficient for the most urgent use
cases (CPUs and memory modules).  In the future, however, the
approach may be extended to cover some more complicated device
offline/online scenarios involving device drivers etc.

The lock_device_hotplug() and unlock_device_hotplug() functions are
introduced because subsequent patches need to put larger pieces of
code under device_hotplug_lock to prevent race conditions between
device offline and removal from happening.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NToshi Kani <toshi.kani@hp.com>
      4f3549d7
  11. 12 4月, 2013 1 次提交
  13. 08 4月, 2013 1 次提交
    • K
      driver core: add uid and gid to devtmpfs · 3c2670e6
      由 Kay Sievers 提交于 
      Some drivers want to tell userspace what uid and gid should be used for
their device nodes, so allow that information to percolate through the
driver core to userspace in order to make this happen.  This means that
some systems (i.e.  Android and friends) will not need to even run a
udev-like daemon for their device node manager and can just rely in
devtmpfs fully, reducing their footprint even more.
Signed-off-by: NKay Sievers <kay@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3c2670e6
  15. 16 3月, 2013 1 次提交
  17. 13 3月, 2013 1 次提交
    • T
      driver/base: implement subsys_virtual_register() · d73ce004
      由 Tejun Heo 提交于 
      Kay tells me the most appropriate place to expose workqueues to
userland would be /sys/devices/virtual/workqueues/WQ_NAME which is
symlinked to /sys/bus/workqueue/devices/WQ_NAME and that we're lacking
a way to do that outside of driver core as virtual_device_parent()
isn't exported and there's no inteface to conveniently create a
virtual subsystem.

This patch implements subsys_virtual_register() by factoring out
subsys_register() from subsys_system_register() and using it with
virtual_device_parent() as the origin directory.  It's identical to
subsys_system_register() other than the origin directory but we aren't
gonna restrict the device names which should be used under it.

This will be used to expose workqueue attributes to userland.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
      d73ce004
  19. 07 2月, 2013 1 次提交
  21. 18 1月, 2013 3 次提交
  23. 27 11月, 2012 2 次提交
  25. 15 11月, 2012 1 次提交
    • L
      driver core / PM: move the calling to device_pm_remove behind the calling to bus_remove_device · 4b6d1f12
      由 LongX Zhang 提交于 
      We hit an hang issue when removing a mmc device on Medfield Android phone by sysfs interface.

device_pm_remove will call pm_runtime_remove which would disable
runtime PM of the device. After that pm_runtime_get* or
pm_runtime_put* will be ignored. So if we disable the runtime PM
before device really be removed, drivers' _remove callback may
access HW even pm_runtime_get* fails. That is bad.

Consider below call sequence when removing a device:
device_del => device_pm_remove
             => class_intf->remove_dev(dev, class_intf)  => pm_runtime_get_sync/put_sync
             => bus_remove_device => device_release_driver => pm_runtime_get_sync/put_sync

remove_dev might call pm_runtime_get_sync/put_sync.
Then, generic device_release_driver also calls pm_runtime_get_sync/put_sync.
Since device_del => device_pm_remove firstly, later _get_sync wouldn't really wake up the device.

I git log -p to find the patch which moves the calling to device_pm_remove ahead.
It's below patch:

commit  775b64d2
Author: Rafael J. Wysocki <rjw@sisk.pl>
Date:   Sat Jan 12 20:40:46 2008 +0100

     PM: Acquire device locks on suspend

     This patch reorganizes the way suspend and resume notifications are
     sent to drivers.  The major changes are that now the PM core acquires
     every device semaphore before calling the methods, and calls to
     device_add() during suspends will fail, while calls to device_del()
     during suspends will block.

     It also provides a way to safely remove a suspended device with the
     help of the PM core, by using the device_pm_schedule_removal() callback
     introduced specifically for this purpose, and updates two drivers (msr
     and cpuid) that need to use it.

As device_pm_schedule_removal is deleted by another patch, we need also revert other parts of the patch,
i.e. move the calling of device_pm_remove after the calling to bus_remove_device.
Signed-off-by: NLongX Zhang <longx.zhang@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      4b6d1f12
  27. 26 10月, 2012 1 次提交
  29. 17 9月, 2012 3 次提交
  31. 19 8月, 2012 1 次提交
  33. 17 8月, 2012 2 次提交
  35. 17 7月, 2012 2 次提交
  37. 12 6月, 2012 1 次提交
  39. 08 5月, 2012 1 次提交
  41. 24 4月, 2012 1 次提交
  43. 19 4月, 2012 1 次提交
  45. 09 3月, 2012 2 次提交
    • G
      driver core: move the deferred probe pointer into the private area · ef8a3fd6
      由 Greg Kroah-Hartman 提交于 
      Nothing outside of the driver core needs to get to the deferred probe
pointer, so move it inside the private area of 'struct device' so no one
tries to mess around with it.

Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ef8a3fd6
    • G
      drivercore: Add driver probe deferral mechanism · d1c3414c
      由 Grant Likely 提交于 
      Allow drivers to report at probe time that they cannot get all the resources
required by the device, and should be retried at a later time.

This should completely solve the problem of getting devices
initialized in the right order.  Right now this is mostly handled by
mucking about with initcall ordering which is a complete hack, and
doesn't even remotely handle the case where device drivers are in
modules.  This approach completely sidesteps the issues by allowing
driver registration to occur in any order, and any driver can request
to be retried after a few more other drivers get probed.

v4: - Integrate Manjunath's addition of a separate workqueue
    - Change -EAGAIN to -EPROBE_DEFER for drivers to trigger deferral
    - Update comment blocks to reflect how the code really works
v3: - Hold off workqueue scheduling until late_initcall so that the bulk
      of driver probes are complete before we start retrying deferred devices.
    - Tested with simple use cases.  Still needs more testing though.
      Using it to get rid of the gpio early_initcall madness, or to replace
      the ASoC internal probe deferral code would be ideal.
v2: - added locking so it should no longer be utterly broken in that regard
    - remove device from deferred list at device_del time.
    - Still completely untested with any real use case, but has been
      boot tested.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dilan Lee <dilee@nvidia.com>
Cc: Manjunath GKondaiah <manjunath.gkondaiah@linaro.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: NDavid Daney <david.daney@cavium.com>
Reviewed-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d1c3414c
  47. 02 2月, 2012 1 次提交
    • G
      drivercore: Output common devicetree information in uevent · 07d57a32
      由 Grant Likely 提交于 
      When userspace needs to find a specific device, it currently isn't easy to
resolve a /sys/devices/ path from a specific device tree node.  Nor is it
easy to obtain the compatible list for devices.

This patch generalizes the code that inserts OF_* values into the uevent
device attribute so that any device that is attached to an OF node will
have that information exported to userspace.  Without this patch only
platform devices and some powerpc-specific busses have access to this
data.

The original function also creates a MODALIAS property for the compatible
list, but that code has not been generalized into the common case because
it has the potential to break module loading on a lot of bus types.  Bus
types are still responsible for their own MODALIAS properties.

Boot tested on ARM and compile tested on PowerPC and SPARC.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Frederic Lambert <frdrc66@gmail.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Mark Brown <broonie@sirena.org.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      07d57a32
  49. 25 1月, 2012 2 次提交
  51. 04 1月, 2012 1 次提交
  53. 15 12月, 2011 1 次提交
    • K
      driver-core: implement 'sysdev' functionality for regular devices and buses · ca22e56d
      由 Kay Sievers 提交于 
      All sysdev classes and sysdev devices will converted to regular devices
and buses to properly hook userspace into the event processing.

There is no interesting difference between a 'sysdev' and 'device' which
would justify to roll an entire own subsystem with different userspace
export semantics. Userspace relies on events and generic sysfs subsystem
infrastructure from sysdev devices, which are currently not properly
available.

Every converted sysdev class will create a regular device with the class
name in /sys/devices/system and all registered devices will becom a children
of theses devices.

For compatibility reasons, the sysdev class-wide attributes are created
at this parent device. (Do not copy that logic for anything new, subsystem-
wide properties belong to the subsystem, not to some fake parent device
created in /sys/devices.)

Every sysdev driver is implemented as a simple subsystem interface now,
and no longer called a driver.

After all sysdev classes are ported to regular driver core entities, the
sysdev implementation will be entirely removed from the kernel.
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      ca22e56d
  55. 08 12月, 2011 1 次提交
    • A
      PM / Driver core: leave runtime PM enabled during system shutdown · fe6b91f4
      由 Alan Stern 提交于 
      Disabling all runtime PM during system shutdown turns out not to be a
good idea, because some devices may need to be woken up from a
low-power state at that time.

The whole point of disabling runtime PM for system shutdown was to
prevent untimely runtime-suspend method calls.  This patch (as1504)
accomplishes the same result by incrementing the usage count for each
device and waiting for ongoing runtime-PM callbacks to finish.  This
is what we already do during system suspend and hibernation, which
makes sense since the shutdown method is pretty much a legacy analog
of the pm->poweroff method.

This fixes a recent regression on some OMAP systems introduced by
commit af8db150 (PM / driver core:
disable device's runtime PM during shutdown).
Reported-and-tested-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      fe6b91f4