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authorRussell King <rmk@arm.linux.org.uk>2005-10-28 09:52:56 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2005-10-28 09:52:56 -0700
commit9480e307cd88ef09ec9294c7d97ebec18e6d2221 (patch)
tree967e26d3a23c24dd52b114d672312c207714308c /Documentation
parenta3a3395e487abc4c1371fe319a8ecbb3913a70a4 (diff)
downloadop-kernel-dev-9480e307cd88ef09ec9294c7d97ebec18e6d2221.zip
op-kernel-dev-9480e307cd88ef09ec9294c7d97ebec18e6d2221.tar.gz
[PATCH] DRIVER MODEL: Get rid of the obsolete tri-level suspend/resume callbacks
In PM v1, all devices were called at SUSPEND_DISABLE level. Then all devices were called at SUSPEND_SAVE_STATE level, and finally SUSPEND_POWER_DOWN level. However, with PM v2, to maintain compatibility for platform devices, I arranged for the PM v2 suspend/resume callbacks to call the old PM v1 suspend/resume callbacks three times with each level in order so that existing drivers continued to work. Since this is obsolete infrastructure which is no longer necessary, we can remove it. Here's an (untested) patch to do exactly that. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/driver-model/driver.txt60
1 files changed, 2 insertions, 58 deletions
diff --git a/Documentation/driver-model/driver.txt b/Documentation/driver-model/driver.txt
index fabaca1..7c26bfa 100644
--- a/Documentation/driver-model/driver.txt
+++ b/Documentation/driver-model/driver.txt
@@ -196,67 +196,11 @@ it into a supported low-power state.
int (*suspend) (struct device * dev, pm_message_t state, u32 level);
-suspend is called to put the device in a low power state. There are
-several stages to successfully suspending a device, which is denoted in
-the @level parameter. Breaking the suspend transition into several
-stages affords the platform flexibility in performing device power
-management based on the requirements of the system and the
-user-defined policy.
-
-SUSPEND_NOTIFY notifies the device that a suspend transition is about
-to happen. This happens on system power state transitions to verify
-that all devices can successfully suspend.
-
-A driver may choose to fail on this call, which should cause the
-entire suspend transition to fail. A driver should fail only if it
-knows that the device will not be able to be resumed properly when the
-system wakes up again. It could also fail if it somehow determines it
-is in the middle of an operation too important to stop.
-
-SUSPEND_DISABLE tells the device to stop I/O transactions. When it
-stops transactions, or what it should do with unfinished transactions
-is a policy of the driver. After this call, the driver should not
-accept any other I/O requests.
-
-SUSPEND_SAVE_STATE tells the device to save the context of the
-hardware. This includes any bus-specific hardware state and
-device-specific hardware state. A pointer to this saved state can be
-stored in the device's saved_state field.
-
-SUSPEND_POWER_DOWN tells the driver to place the device in the low
-power state requested.
-
-Whether suspend is called with a given level is a policy of the
-platform. Some levels may be omitted; drivers must not assume the
-reception of any level. However, all levels must be called in the
-order above; i.e. notification will always come before disabling;
-disabling the device will come before suspending the device.
-
-All calls are made with interrupts enabled, except for the
-SUSPEND_POWER_DOWN level.
+suspend is called to put the device in a low power state.
int (*resume) (struct device * dev, u32 level);
-Resume is used to bring a device back from a low power state. Like the
-suspend transition, it happens in several stages.
-
-RESUME_POWER_ON tells the driver to set the power state to the state
-before the suspend call (The device could have already been in a low
-power state before the suspend call to put in a lower power state).
-
-RESUME_RESTORE_STATE tells the driver to restore the state saved by
-the SUSPEND_SAVE_STATE suspend call.
-
-RESUME_ENABLE tells the driver to start accepting I/O transactions
-again. Depending on driver policy, the device may already have pending
-I/O requests.
-
-RESUME_POWER_ON is called with interrupts disabled. The other resume
-levels are called with interrupts enabled.
-
-As with the various suspend stages, the driver must not assume that
-any other resume calls have been or will be made. Each call should be
-self-contained and not dependent on any external state.
+Resume is used to bring a device back from a low power state.
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