From: Jean Pihet <j-pihet@xxxxxx>
This patch set is in an RFC state, for review and comments.
In order to implement the new class in PM QoS the following changes have been made:
1. Add a new PM QoS class for device wake-up constraints (PM_QOS_DEV_WAKEUP_LATENCY).
Due to the per-device nature of the new class the constraints lists are stored inside the device dev_pm_info struct instead of the internal per-class constraints lists.
The new class is only available from kernel drivers and so is not exported to user space.
2. Make the pm_qos_add_request API more generic by using a struct pm_qos_parameters parameter. This allows easy extension in the future.
3. Upon a change of the strongest constraint in the PM_QOS_DEV_WAKEUP_LATENCY class a notification chain mechanism is used to take action on the system. This is the proposed way to have PM QoS and the platform dependant code to interact with each other, cf. 4 below.
The notification mechanism now passes the constraint request struct ptr in order for the notifier callback to have access to the full set of constraint data, e.g. the struct device ptr.
4. cpuidle interaction with the OMAP3 cpuidle handler
Since cpuidle is a CPU centric framework it decides the MPU next power state based on the MPU exit_latency and target_residency figures.
The rest of the power domains get their next power state programmed from the PM_QOS_DEV_WAKEUP_LATENCY class of the PM QoS framework, via the device wake-up latency constraints.
Note: the exit_latency and target_residency figures of the MPU include the MPU itself and the peripherals needed for the MPU to execute instructions (e.g. main memory, caches, IRQ controller, MMU etc).
Some of those peripherals can belong to other power domains than the MPU subsystem and so the corresponding latencies must be included in this figure.
5. Update the pm_qos_add_request callers to the generic API
6. Minor clean-ups and rename of struct fields
Questions:
1. How to retrieve the device ptr from a given device driver in order to add a constraint on it?
2. The device struct has been extended with the power domain information. Can this be used to apply the constraints on power domains, as proposed by [1]?
On-going developments, patches in preparation:
1. write Documentation for the new PM QoS class
2. validate the constraints framework on OMAP3&4
3. refine the power domains wake-up latency and the cpuidle figures
[1] http://marc.info/?l=linux-omap&m=130451613408148&w=2
Based on the master branch of the linux-omap git tree (3.0.0-rc3). Compile tested only using OMAP and x86 generic defconfigs.
Jean Pihet (8):
PM: add a per-device wake-up latency constraints plist
PM: extend PM QoS with per-device wake-up constraints
OMAP PM: create a PM layer plugin for per-device constraints
OMAP2+: powerdomain: control power domains next state
OMAP3: powerdomain data: add wake-up latency figures
OMAP2+: omap_hwmod: manage the wake-up latency constraints
OMAP: PM CONSTRAINTS: implement the devices wake-up latency
constraints
OMAP2+: cpuidle only influences the MPU state
Vishwanath BS (1):
OMAP4: powerdomain data: add wake-up latency figures
arch/arm/mach-omap2/cpuidle34xx.c | 42 +---
arch/arm/mach-omap2/omap_hwmod.c | 26 ++-
arch/arm/mach-omap2/pm.h | 17 ++-
arch/arm/mach-omap2/powerdomain.c | 187 ++++++++++++++
arch/arm/mach-omap2/powerdomain.h | 33 +++-
arch/arm/mach-omap2/powerdomains3xxx_data.c | 77 ++++++
arch/arm/mach-omap2/powerdomains44xx_data.c | 85 +++++++
arch/arm/plat-omap/Kconfig | 7 +
arch/arm/plat-omap/Makefile | 1 +
arch/arm/plat-omap/i2c.c | 20 --
arch/arm/plat-omap/include/plat/omap-pm.h | 128 ----------
arch/arm/plat-omap/include/plat/omap_hwmod.h | 2 +
arch/arm/plat-omap/omap-pm-constraints.c | 344 ++++++++++++++++++++++++++
arch/arm/plat-omap/omap-pm-noop.c | 89 -------
drivers/base/power/main.c | 1 +
drivers/i2c/busses/i2c-omap.c | 35 ++-
drivers/media/video/via-camera.c | 5 +-
drivers/net/e1000e/netdev.c | 9 +-
drivers/net/wireless/ipw2x00/ipw2100.c | 6 +-
include/linux/pm.h | 2 +
include/linux/pm_qos_params.h | 40 ++--
kernel/pm_qos_params.c | 142 ++++++-----
sound/core/pcm_native.c | 8 +-
23 files changed, 939 insertions(+), 367 deletions(-)
create mode 100644 arch/arm/plat-omap/omap-pm-constraints.c
--
1.7.4.1
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
