Power domains might have parent domains assigned that are automatically
managed by the PM domain core. In particular, parent domains are
automatically powered on/off and setting performance states on child
domains are propagated to parent domains (e.g. using an OPP table from the
device tree).
Currently the parent performance state is always adjusted before the
performance state of the child domain, which is a problem for some cases
when scaling down the performance state. More exactly, it may lead to that
the parent domain could run in a lower performance state, than what is
required by the child domain.
To fix the behaviour, let's differentiate between scaling up/down and
adjust the order of operations:
- When scaling up, parent domains should be adjusted before the child
domain. In case of an error, the rollback happens in reverse order.
- When scaling down, parent domains should be adjusted after the child
domain, in reverse order, just as if we would rollback scaling up.
In case of an error, the rollback happens in normal order (just as
if we would normally scale up).
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20240103-genpd-perf-order-v2-1-eeecfc55624b@gerhold.net
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Pull driver core updates from Greg KH:
"Here are the set of driver core and kernfs changes for 6.8-rc1.
Nothing major in here this release cycle, just lots of small cleanups
and some tweaks on kernfs that in the very end, got reverted and will
come back in a safer way next release cycle.
Included in here are:
- more driver core 'const' cleanups and fixes
- fw_devlink=rpm is now the default behavior
- kernfs tiny changes to remove some string functions
- cpu handling in the driver core is updated to work better on many
systems that add topologies and cpus after booting
- other minor changes and cleanups
All of the cpu handling patches have been acked by the respective
maintainers and are coming in here in one series. Everything has been
in linux-next for a while with no reported issues"
* tag 'driver-core-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (51 commits)
Revert "kernfs: convert kernfs_idr_lock to an irq safe raw spinlock"
kernfs: convert kernfs_idr_lock to an irq safe raw spinlock
class: fix use-after-free in class_register()
PM: clk: make pm_clk_add_notifier() take a const pointer
EDAC: constantify the struct bus_type usage
kernfs: fix reference to renamed function
driver core: device.h: fix Excess kernel-doc description warning
driver core: class: fix Excess kernel-doc description warning
driver core: mark remaining local bus_type variables as const
driver core: container: make container_subsys const
driver core: bus: constantify subsys_register() calls
driver core: bus: make bus_sort_breadthfirst() take a const pointer
kernfs: d_obtain_alias(NULL) will do the right thing...
driver core: Better advertise dev_err_probe()
kernfs: Convert kernfs_path_from_node_locked() from strlcpy() to strscpy()
kernfs: Convert kernfs_name_locked() from strlcpy() to strscpy()
kernfs: Convert kernfs_walk_ns() from strlcpy() to strscpy()
initramfs: Expose retained initrd as sysfs file
fs/kernfs/dir: obey S_ISGID
kernel/cgroup: use kernfs_create_dir_ns()
...
It seems reasonable to collect the core parts for the generic PM domain,
along with its corresponding provider drivers. Therefore let's move the
files from drivers/base/power/ to drivers/pmdomain/ and while at it, let's
also rename the files accordingly.
Moreover, let's also update MAINTAINERS to reflect the update.
Cc: Kevin Hilman <khilman@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20231213113305.29098-1-ulf.hansson@linaro.org
