Date:	Tue, 14 May 2013 21:56:33 -0700
From:	Sonny Rao <sonnyrao@...omium.org>
To:	Zhang Rui <rui.zhang@...el.com>
Cc:	linux-pm@...r.kernel.org, Sameer Nanda <snanda@...omium.org>,
	"Triplett, Josh" <josh.triplett@...el.com>,
	Olof <olofj@...omium.org>, len.brown@...el.com,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Fans at full speed after resume

On Tue, May 14, 2013 at 9:34 PM, Sonny Rao <sonnyrao@...omium.org> wrote:
> On Tue, May 14, 2013 at 9:29 PM, Zhang Rui <rui.zhang@...el.com> wrote:
>> On Wed, 2013-05-15 at 12:26 +0800, Zhang Rui wrote:
>>> please
>>>
>>> On Tue, 2013-05-14 at 21:18 -0700, Sonny Rao wrote:
>>> > Hi, I've seen a regression in kernels since 3.7 on x86 devices where
>>> > the kernel turns the system fans on to max speed after resuming from
>>> > ram.  Other people have noticed it as well, for example see
>>> > https://bugzilla.redhat.com/show_bug.cgi?id=895276
>>> >
>>> please check if this is a duplicate of bug
>>> https://bugzilla.kernel.org/show_bug.cgi?id=56591
>> or you can try 3.10-rc1 to see if the problem still exists or not.
>
> Ok, I patched in the fix from that bugzilla --
> 928c5edbe6f7cb0d1c71bc2353d091bc5b114fe3
> but I'm still seeing the issue, I'll try 3.10-rc1 next
>

3.10-rc1 seems good
3.9.2 is okay, though fans do seem to be on more for a while after
resume, it eventually turns off
3.8.13 seems to still be broken, with fans at maximum

>>
>> thanks,
>> rui
>>> > For example on the Samsung 550 Chromebook, we have one thermal zone
>>> > and have 5 cooling_devices, 0-4, which correspond to 5 possible fan
>>> > speeds.  Under typical idle, only cooling_device4 and maybe
>>> > cooling_device3 are active, depending on temperature:
>>> >
>>> > cat /sys/class/thermal/cooling_device[01234]/cur_state
>>> > /sys/class/thermal/thermal_zone0/temp
>>> > 0
>>> > 0
>>> > 0
>>> > 0
>>> > 1
>>> > 57000
>>> >
>>> > however after a suspend/resume, we see that cooling_devices 0 and 1
>>> > become active:
>>> > cat /sys/class/thermal/cooling_device[01234]/cur_state
>>> > /sys/class/thermal/thermal_zone0/temp
>>> > 1
>>> > 1
>>> > 0
>>> > 0
>>> > 1
>>> > 54000
>>> >
>>> > and it seems to stay that way, even though the temperature is low
>>> > enough that the fan shouldn't be running at that speed.  If I manually
>>> > disable cooling_devices 0 and 1 then fan control works normally again.
>>> >
>>> > I started bisecting it and was able to do so up until this commit:
>>> > commit 29b19e250434c6193c8b8e4c34c9c6284dd4f101
>>> > Merge: 125c4c7 c072fed
>>> > Author:     Len Brown <len.brown@...el.com>
>>> > AuthorDate: Tue Oct 9 01:35:52 2012 -0400
>>> > Commit:     Len Brown <len.brown@...el.com>
>>> > CommitDate: Tue Oct 9 01:35:52 2012 -0400
>>> >
>>> >     Merge branch 'release' of
>>> > git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux into
>>> > thermal
>>> >
>>> > unfortunately, I'm not able to successfully do a suspend/resume on the
>>> > commits in that merge, so I wasn't able to bisect down to the exact
>>> > commit.
>>> >
>>> > I did confirm that one parent of the merge is okay: commit
>>> > 125c4c706b680c7831f0966ff873c1ad0354ec25 idr: rename MAX_LEVEL to
>>> > MAX_IDR_LEVEL
>>> >
>>> > so I think it falls somewhere in this list of commits:
>>> > c072fed95c9855a920c114d7fa3351f0f54ea06e...e3f25e6e5836c4790fbe395ff42e241f372d859d
>>> >
>>> > c072fed9 thermal: Exynos: Fix NULL pointer dereference in
>>> > exynos_unregister_thermal()
>>> > a4b6fec9 Thermal: Fix bug on cpu_cooling, cooling device's id conflict problem.
>>> > 79e093c3 thermal: exynos: Use devm_* functions
>>> > 17be868e ARM: exynos: add thermal sensor driver platform data support
>>> > 7e0b55e6 thermal: exynos: register the tmu sensor with the kernel thermal layer
>>> > f22d9c03c thermal: exynos5: add exynos5250 thermal sensor driver support
>>> > c48cbba6 hwmon: exynos4: move thermal sensor driver to driver/thermal directory
>>> > 02361418 thermal: add generic cpufreq cooling implementation
>>> > a7a3b8c8 Fix a build error.
>>> > 204dd1d3 thermal: Fix potential NULL pointer accesses
>>> > 1e426ffdd thermal: add Renesas R-Car thermal sensor support
>>> > 79a49168 thermal: fix potential out-of-bounds memory access
>>> > f4a821ce6 Thermal: Introduce locking for cdev.thermal_instances list.
>>> > 908b9fb79 Thermal: Unify the code for both active and passive cooling
>>> > ce119f832 Thermal: Introduce simple arbitrator for setting device cooling state
>>> > b5e4ae62 Thermal: List thermal_instance in thermal_cooling_device.
>>> > cddf31b3b Thermal: Rename thermal_instance.node to thermal_instance.tz_node.
>>> > 2d374139 Thermal: Rename thermal_zone_device.cooling_devices
>>> > b81b6ba3 Thermal: rename structure thermal_cooling_device_instance to
>>> > thermal_instance
>>> > 4ae46befb Thermal: Introduce thermal_zone_trip_update()
>>> > 1b7ddb84 Thermal: Remove tc1/tc2 in generic thermal layer.
>>> > 601f3d424 Thermal: Introduce .get_trend() callback.
>>> > 9d99842f9 Thermal: set upper and lower limits
>>> > 74051ba5 Thermal: Introduce cooling states range support
>>> >
>>> > When I get time, I'll try to rebase those commits onto the IDR commit
>>> > and see if I can get a better bisect.  Any insights into the problem
>>> > would be appreciated, thanks.
>>>
>>>
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>>
>>
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