From: Jean Pihet <j-pihet@xxxxxx>
High level implementation:
1. Preparation of the PM QoS for the addition of a device PM QoS constraints
framework:
. rename and move of the PM QoS implementation files to kernel/power/qos.c
and include/linux/pm_qos.h
. rename of API parameters and internal fields names
. Move around the PM QoS misc devices management code for better readability
. re-organize the internal data structs
. generalize and export the constraints management core code
2. Implementation of the per-device PM QoS constraints:
. create drivers/base/power/qos.c for the implementation
. create a device PM QoS API, which calls the PM QoS constraints management
core code
. the per-device latency constraints data strctures are stored in the device
dev_pm_info struct
. the device PM code calls the init and destroy of the per-device constraints
data struct in order to support the dynamic insertion and removal of the
devices in the system.
. to minimize the data usage by the per-device constraints, the data struct
is only allocated at the first call to dev_pm_qos_add_request. The data
is later free'd when the device is removed from the system
. per-device notification callbacks can be registered and called upon a
change to the aggregated constraint value
. a global mutex protects the constraints users from the data being
allocated and free'd.
3. add a global notification mechanism for the device constraints
. add a global notification chain that gets called upon changes to the
aggregated constraint value for any device.
. the notification callbacks are passing the full constraint request data
in order for the callees to have access to it. The current use is for the
platform low-level code to access the target device of the constraint
Questions:
1. the user space API is still under discussions on linux-omap and linux-pm MLs,
cf. [1]. The idea is to add a user-space API for the devices constratins
PM QoS, using a sysfs entry per device
[1] http://marc.info/?l=linux-omap&m=131232344503327&w=2
ToDo:
1. write Documentation for the new PM QoS class, once the code is agreed on
2. submit patches for the OMAP low level code to control the power domains
states from the device constraints, using a global notification callback
Based on the master branch of the linux-omap git tree (3.1.0-rc1). Compile
tested using OMAP and x86 generic defconfigs.
Tested on OMAP3 Beagleboard (ES2.x).
Need testing on platforms other than OMAP, because of the impact on the
device insertion/removal in device_pm_add/remove
Changelog:
v6:
. Split the code into the generic PM QoS code and OMAP specific code; only
the PM QoS is included in this release
. Added copyright in the device PM QoS code
. Re-organize the code for improved readability
. Changed the dev_pm_qos_* API functions type to int and improved the
error checking
. Added kerneldoc compliant functions headers
v5:
. Added a global mutex to protect the per-device data allocation/free from
the users
. More robust error checking in the device PM QoS code
. Clean-up of the device PM QoS code: refactor some duplicated code, removal
of unneeded includes
v4:
. Complete devices PM QoS re-design:
. Separation from the existing PM QoS classes by adding a device PM QoS
API. The device code is re-using the PM QoS core code for constraints
lists management and notification mechanism
. Addition of a devices PM QoS global notification mechanism, for interaction
with the low level platform code
v3:
. Complete PM QoS re-design after the comments on MLs
. Patch set split up for improved readability and easier maintenance
v2:
. Rework after comments on the mailing lists
. Added a notification of device insertion/removal from the device PM framework
. Validated on OMAP3 HW
v1:
. Initial implementation
Jean Pihet (7):
PM QoS: move and rename the implementation files
PM QoS: minor clean-ups
PM QoS: code re-organization
PM QoS: re-organize data structs
PM QoS: generalize and export the constraints management code
PM QoS: implement the per-device PM QoS constraints
PM QoS: add a global notification mechanism for the device
constraints
arch/arm/mach-msm/clock.c | 2 +-
drivers/acpi/processor_idle.c | 2 +-
drivers/base/power/Makefile | 4 +-
drivers/base/power/main.c | 3 +
drivers/base/power/qos.c | 400 ++++++++++++++++++++++++++
drivers/cpuidle/cpuidle.c | 2 +-
drivers/cpuidle/governors/ladder.c | 2 +-
drivers/cpuidle/governors/menu.c | 2 +-
drivers/media/video/via-camera.c | 4 +-
drivers/net/e1000e/netdev.c | 2 +-
drivers/net/wireless/ipw2x00/ipw2100.c | 4 +-
include/linux/netdevice.h | 4 +-
include/linux/pm.h | 9 +
include/linux/pm_qos.h | 147 ++++++++++
include/linux/pm_qos_params.h | 38 ---
include/sound/pcm.h | 4 +-
kernel/Makefile | 2 +-
kernel/pm_qos_params.c | 481 -------------------------------
kernel/power/Makefile | 2 +-
kernel/power/qos.c | 490 ++++++++++++++++++++++++++++++++
net/mac80211/main.c | 2 +-
net/mac80211/mlme.c | 2 +-
net/mac80211/scan.c | 2 +-
sound/core/pcm_native.c | 2 +-
24 files changed, 1071 insertions(+), 541 deletions(-)
create mode 100644 drivers/base/power/qos.c
create mode 100644 include/linux/pm_qos.h
delete mode 100644 include/linux/pm_qos_params.h
delete mode 100644 kernel/pm_qos_params.c
create mode 100644 kernel/power/qos.c
--
1.7.4.1
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