From: Jarkko Nikula <jarkko.nikula@linux.intel.com>
To: John Stultz <john.stultz@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Wolfram Sang <wsa@the-dreams.de>,
linux-i2c@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>,
zhangfei <zhangfei.gao@linaro.org>,
Guodong Xu <guodong.xu@linaro.org>,
Amit Pundir <amit.pundir@linaro.org>
Subject: Re: Issue with i2c-designware-platdrv's suspend/runtime-suspend handling
Date: Tue, 31 Jan 2017 11:32:44 +0200 [thread overview]
Message-ID: <0c44fe3a-b6d7-c947-0137-be4d33e132d7@linux.intel.com> (raw)
In-Reply-To: <CALAqxLVzW6Di5GM6iXi7PUen2Dq0TZ=awXYXY74BUK02Nfwm0Q@mail.gmail.com>
On 01/31/2017 12:05 AM, John Stultz wrote:
> On Tue, Jan 24, 2017 at 2:03 PM, John Stultz <john.stultz@linaro.org> wrote:
>> Doing some further debugging, it seems the problem is that the device
>> is being runtime suspended, and then at suspend time, we're calling
>> the same logic, calling i2c_dw_plat_prepare_clk, which causes the clk
>> count warning.
>>
>> Removing the runtime pm ops:
>> - SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
>> +// SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
>>
>> seems to avoid the warning, but clearly isn't ideal. :)
>>
>> Should there be some logic keep track of the suspend state for the
>> dw_i2c_dev device so we don't try to suspend (or resume) it twice? Or
>> is there something else I'm missing to keep this from happening?
>
> Ping? Any thoughts on how best to fix this? I'm leaning towards
> adding a suspended state to the struct dw_i2c_dev. Any objections?
>
I wonder why device PM doesn't take care of this?
If i2c-designware is enumerated from ACPI then drivers/acpi/device_pm.c:
acpi_subsys_suspend() resumes devices suspended at run time before
system suspend so dw_i2c_plat_suspend() won't be called twice.
But still I think device PM should not attempt to suspend already
suspended device?
--
Jarkko
prev parent reply other threads:[~2017-01-31 9:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-24 22:03 Issue with i2c-designware-platdrv's suspend/runtime-suspend handling John Stultz
2017-01-30 22:05 ` John Stultz
2017-01-31 9:32 ` Jarkko Nikula [this message]
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