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Date: Wed, 28 Oct 2015 10:33:11 +0000
From: Javi Merino <javi.merino@....com>
To: rui.zhang@...el.com, Chen Yu <yu.c.chen@...el.com>
Cc: edubezval@...il.com, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH 2/3][v2] Thermal: handle thermal zone device properly
during system sleep
Hi Yu,
some minor nits below. Other than that, you can add my
Reviewed-by: Javi Merino <javi.merino@....com>
On Mon, Oct 26, 2015 at 11:14:31AM +0800, Chen Yu wrote:
> From: Zhang Rui <rui.zhang@...el.com>
>
> Current thermal code does not handle system sleep well because
> 1. the cooling device cooling state may be changed during suspend
> 2. the previous temperature reading becomes invalid after resumed because
> it is got before system sleep
> 3. updating thermal zone device during suspending/resuming
> is wrong because some devices may have already been suspended
> or may have not been resumed.
>
> Thus, the proper way to do this is to cancel all thermal zone
> device update requirements during suspend/resume, and after all
> the devices have been resumed, reset and update every registered
> thermal zone devices.
>
> This also fixes a regression introduced by:
> Commit 19593a1fb1f6 ("ACPI / fan: convert to platform driver")
> Because, with above commit applied, all the fan devices are attached
> to the acpi_general_pm_domain, and they are turned on by the pm_domain
> automatically after resume, without the awareness of thermal core.
>
> CC: <stable@...r.kernel.org> #3.18+
> Reference: https://bugzilla.kernel.org/show_bug.cgi?id=78201
> Reference: https://bugzilla.kernel.org/show_bug.cgi?id=91411
> Tested-by: Manuel Krause <manuelkrause@...scape.net>
> Tested-by: szegad <szegadlo@...zta.onet.pl>
> Tested-by: prash <prash.n.rao@...il.com>
> Tested-by: amish <ammdispose-arch@...oo.com>
> Tested-by: Matthias <morpheusxyz123@...oo.de>
> Signed-off-by: Zhang Rui <rui.zhang@...el.com>
> Signed-off-by: Chen Yu <yu.c.chen@...el.com>
> ---
> drivers/thermal/thermal_core.c | 45 +++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 44 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 682bc1e..abeb995 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -37,6 +37,7 @@
> #include <linux/of.h>
> #include <net/netlink.h>
> #include <net/genetlink.h>
> +#include <linux/suspend.h>
>
> #define CREATE_TRACE_POINTS
> #include <trace/events/thermal.h>
> @@ -59,6 +60,8 @@ static LIST_HEAD(thermal_governor_list);
> static DEFINE_MUTEX(thermal_list_lock);
> static DEFINE_MUTEX(thermal_governor_lock);
>
> +static atomic_t in_suspend;
> +
> static struct thermal_governor *def_governor;
>
> static struct thermal_governor *__find_governor(const char *name)
> @@ -554,6 +557,9 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
> {
> int count;
>
> + if (atomic_read(&in_suspend))
> + return;
> +
> if (!tz->ops->get_temp)
> return;
>
> @@ -2155,9 +2161,39 @@ static void thermal_unregister_governors(void)
> thermal_gov_power_allocator_unregister();
> }
>
> +static int thermal_pm_notify(struct notifier_block *nb,
> + unsigned long mode, void *_unused)
> +{
> + struct thermal_zone_device *tz;
> +
> + switch (mode) {
> + case PM_HIBERNATION_PREPARE:
> + case PM_RESTORE_PREPARE:
> + case PM_SUSPEND_PREPARE:
> + atomic_set(&in_suspend, 1);
> + break;
> + case PM_POST_HIBERNATION:
> + case PM_POST_RESTORE:
> + case PM_POST_SUSPEND:
> + atomic_set(&in_suspend, 0);
> + list_for_each_entry(tz, &thermal_tz_list, node) {
> + thermal_zone_device_reset(tz);
> + thermal_zone_device_update(tz);
> + }
> + break;
> + default:
> + break;
> + }
> + return 0;
> +}
> +
> +static struct notifier_block thermal_pm_nb = {
> + .notifier_call = thermal_pm_notify,
> +};
> +
> static int __init thermal_init(void)
> {
> - int result;
> + int result, notifier_result;
>
> result = thermal_register_governors();
> if (result)
> @@ -2175,6 +2211,12 @@ static int __init thermal_init(void)
> if (result)
> goto exit_netlink;
>
> + notifier_result = register_pm_notifier(&thermal_pm_nb);
No need to define a new variable, you can use result.
> + if (notifier_result)
> + pr_err("Thermal: Can not register suspend notifier"
pr_warn ?
> + "for thermal framework, return %d\n",
Please keep the string in the same line, don't break it. I know that
checkpatch.pl complains, but the CodingStyle says don't break them:
"However, never break user-visible strings such as printk messages,
because that breaks the ability to grep for them"
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/CodingStyle#n86
Cheers,
Javi
> + notifier_result);
> +
> return 0;
>
> exit_netlink:
> @@ -2194,6 +2236,7 @@ error:
>
> static void __exit thermal_exit(void)
> {
> + unregister_pm_notifier(&thermal_pm_nb);
> of_thermal_destroy_zones();
> genetlink_exit();
> class_unregister(&thermal_class);
> --
> 1.8.4.2
>
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