Messages in this thread Patch in this message | | | Date | Mon, 4 Feb 2019 15:37:20 +0000 | From | Sudeep Holla <> | Subject | Re: [RFC PATCH] drivers core: cpu: add hotplug callback to update cpu_dev state to resumed |
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On Thu, Jan 31, 2019 at 04:05:59PM +0000, Sudeep Holla wrote: > On Thu, Jan 31, 2019 at 12:48:49AM +0100, Rafael J. Wysocki wrote: > > On Friday, January 25, 2019 4:09:06 PM CET Sudeep Holla wrote: > > > The sysfs for the cpu caches are managed by adding devices with cpu > > > as the parent in cpu_device_create() when secondary cpu is brought > > > onlin. Generally when the secondary CPUs are hotplugged back is as part > > > of resume from suspend-to-ram, we call cpu_device_create() from the cpu > > > hotplug state machine while the cpu device associated with that CPU is > > > not yet ready to be resumed as the device_resume() call happens bit later. > > > It's not really needed to set the flag is_prepared for cpu devices are > > > they are mostly pseudo device and hotplug framework deals with state > > > machine and not managed through the cpu device. > > > > > > This often results in annoying warning when resuming: > > > Enabling non-boot CPUs ... > > > CPU1: Booted secondary processor > > > cache: parent cpu1 should not be sleeping > > > CPU1 is up > > > CPU2: Booted secondary processor > > > cache: parent cpu2 should not be sleeping > > > CPU2 is up > > > .... and so on. > > > > > > Just fix the warning by updating the device state quite early. > > > > > > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > > > Reported-by: Jisheng Zhang <jszhang@marvell.com> > > > Reported-by: Steve Longerbeam <slongerbeam@gmail.com> > > > Reported-by: Eugeniu Rosca <erosca@de.adit-jv.com> > > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > > --- > > > drivers/base/cpu.c | 20 +++++++++++++++++++- > > > include/linux/cpuhotplug.h | 1 + > > > 2 files changed, 20 insertions(+), 1 deletion(-) > > > > > > Hi Rafael, > > > > > > This is getting reported for quite some time. Let me know if you have > > > better solution to fix this harmless yet annoying warnings during system > > > resume. > > > > I'd rather have a flag in struct dev_pm_info that will cause the message to > > be suppressed if set. > > > > It could be used for other purposes too then in princple (like skipping the > > creation of empty "power" attr groups in sysfs for devices that don't > > need them etc.). > > > Thanks for the suggestion. I did quick hack and came up with something > below. I wanted to run through you once before I materialise it into > a formal patch to check if I understood your suggestion correctly. > We can move no_pm_required outside dev_pm_info struct and rename with > any better names. >
Sorry for the nag, since the title has RFC, thought there are chances of this getting lost. Let me know if the below idea aligns with your suggestion ?
Regards, Sudeep > -->8 > > diff --git i/drivers/base/cpu.c w/drivers/base/cpu.c > index eb9443d5bae1..b61f9772ed33 100644 > --- i/drivers/base/cpu.c > +++ w/drivers/base/cpu.c > @@ -379,6 +379,7 @@ int register_cpu(struct cpu *cpu, int num) > cpu->dev.bus->uevent = cpu_uevent; > #endif > cpu->dev.groups = common_cpu_attr_groups; > + cpu->dev.power.no_pm_required = true; > if (cpu->hotpluggable) > cpu->dev.groups = hotplugable_cpu_attr_groups; > error = device_register(&cpu->dev); > @@ -427,6 +428,7 @@ __cpu_device_create(struct device *parent, void *drvdata, > dev->parent = parent; > dev->groups = groups; > dev->release = device_create_release; > + dev->power.no_pm_required = true; > dev_set_drvdata(dev, drvdata); > > retval = kobject_set_name_vargs(&dev->kobj, fmt, args); > diff --git i/drivers/base/power/main.c w/drivers/base/power/main.c > index 0992e67e862b..ed1b133f73db 100644 > --- i/drivers/base/power/main.c > +++ w/drivers/base/power/main.c > @@ -124,6 +124,8 @@ void device_pm_unlock(void) > */ > void device_pm_add(struct device *dev) > { > + if (dev->power.no_pm_required) > + return; > pr_debug("PM: Adding info for %s:%s\n", > dev->bus ? dev->bus->name : "No Bus", dev_name(dev)); > device_pm_check_callbacks(dev); > @@ -142,6 +144,8 @@ void device_pm_add(struct device *dev) > */ > void device_pm_remove(struct device *dev) > { > + if (dev->power.no_pm_required) > + return; > pr_debug("PM: Removing info for %s:%s\n", > dev->bus ? dev->bus->name : "No Bus", dev_name(dev)); > complete_all(&dev->power.completion); > diff --git i/drivers/base/power/sysfs.c w/drivers/base/power/sysfs.c > index d713738ce796..54c1bfec396e 100644 > --- i/drivers/base/power/sysfs.c > +++ w/drivers/base/power/sysfs.c > @@ -648,6 +648,9 @@ int dpm_sysfs_add(struct device *dev) > { > int rc; > > + if (dev->power.no_pm_required) > + return 0; > + > rc = sysfs_create_group(&dev->kobj, &pm_attr_group); > if (rc) > return rc; > diff --git i/include/linux/pm.h w/include/linux/pm.h > index 0bd9de116826..300ab9f0b858 100644 > --- i/include/linux/pm.h > +++ w/include/linux/pm.h > @@ -592,6 +592,7 @@ struct dev_pm_info { > bool is_suspended:1; /* Ditto */ > bool is_noirq_suspended:1; > bool is_late_suspended:1; > + bool no_pm_required:1; > bool early_init:1; /* Owned by the PM core */ > bool direct_complete:1; /* Owned by the PM core */ > u32 driver_flags;
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