Summary:
Address the following issues for port power control:
1/ Port power policy needs 'connector' awareness.
2/ Reliable port power control requires coordination with khubd.
3/ Userspace needs full control, but also help coordinating port
power policy.
Even with these changes port power control still defaults to disabled
(ports are always on). This is 3.14 material.
Details:
1/ Port power policy needs 'connector' awareness.
It is a recipe for unintended device disconnects to turn off a
port while leaving its peer active. The attached device, provided
it is not a hub may, switch from the USB3 connection to USB2.
Introduce a 'connector' object to track ports from different hcds
(for example the two hcds provided by XHCI). A 'connector' is
distinct from 'companion' ports which share the same data lines
across multiple hcds. Port-connector membership data comes from
platorm firmware.
2/ Reliable port power control requires coordination with khubd.
The existing implementation makes attempts to mitigate the damage of
khubd running in the middle of a port power control event, but
makes no guarantees. We need to support both suspending hubs with
live ports (to receive wakeup events) and fully powering down the
port when userspace policy allows.
3/ Userspace needs full control, but also help coordinating port
power policy.
Augment the existing controls portX/power/pm_qos_no_power_off and
portX/power/control with connector awareness (i.e. propagate control
settings across ports in a connector), but also add policies based
on the connector type ('hotplug' ports never power down as compared
to 'hardwired').
Even with these changes port power control still defaults to on.
When enabled (pm_qos_no_power_off=0) it tries to do the right thing
for connectors and hotplug capable ports. At all times userspace
can override what acpi has defined (pm_qos_no_notify_flags to stop
propagating settings to 'peers', connect_type to override whether
the port is hotplug capable, or usbcore.noacpi to turn it all off).
---
Dan Williams (15):
usb: xhci: fix memleak on module removal
usbcore: introduce usb_domain for tracking port-connector relationships
usbcore: add sysfs linkage for connector peers
PM / Runtime: Allow drivers to intercept pm qos flag changes
usbcore: port power policy / prep for usb_port as usb_device parent
usbcore: make usb_port a proper parent of a usb_device
usbcore: pm_runtime honor children
usbcore: kill ->is_power_on and ->did_runtime_put
usbcore: convert khubd to a workqueue and flush khubd on port power off
usbcore: cleanup hub_port_connect_change and hub_power_on
usbcore: power down peer port on endpoint connect
usbcore: allow the connect_type of ports to be changed
usbcore: show port power policy
usbcore: add usbcore.noacpi
checkpatch: allow list_for_each helper macros
Documentation/ABI/testing/sysfs-devices-power | 21 +
Documentation/kernel-parameters.txt | 4
Documentation/power/pm_qos_interface.txt | 15 -
drivers/base/power/qos.c | 48 +++
drivers/base/power/sysfs.c | 45 ++-
drivers/usb/core/Kconfig | 4
drivers/usb/core/Makefile | 1
drivers/usb/core/hcd-pci.c | 17 +
drivers/usb/core/hcd.c | 2
drivers/usb/core/hub.c | 252 ++++-----------
drivers/usb/core/hub.h | 29 +-
drivers/usb/core/port.c | 171 +++++++---
drivers/usb/core/usb-acpi.c | 76 ++++
drivers/usb/core/usb-platform.c | 425 +++++++++++++++++++++++++
drivers/usb/core/usb-platform.h | 56 +++
drivers/usb/core/usb.c | 14 +
drivers/usb/host/xhci-pci.c | 16 +
drivers/usb/host/xhci.c | 6
include/linux/pm.h | 5
include/linux/pm_qos.h | 5
include/linux/usb/hcd.h | 9 +
scripts/checkpatch.pl | 1
22 files changed, 931 insertions(+), 291 deletions(-)
create mode 100644 drivers/usb/core/usb-platform.c
create mode 100644 drivers/usb/core/usb-platform.h
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