Messages in this thread Patch in this message | | | Date | Thu, 31 Jan 2019 16:05:59 +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 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.
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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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