linux-kernel - Re: [PATCH 5/6] mfd: cros_ec_dev: Check communication with ec at resume

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Message-ID: <CAMHSBOXBu7pRmifePJ82cj3MorRXXGqfdDSCrDJ7qwJ8YBarrA@mail.gmail.com>
Date:   Fri, 23 Feb 2018 01:01:45 -0800
From:   Gwendal Grignou <gwendal@...gle.com>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Gwendal Grignou <gwendal@...omium.org>,
        Lee Jones <lee.jones@...aro.org>,
        Guenter Roeck <groeck@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        kernel@...labora.com
Subject: Re: [PATCH 5/6] mfd: cros_ec_dev: Check communication with ec at resume

On Thu, Feb 22, 2018 at 1:41 AM, Enric Balletbo i Serra
<enric.balletbo@...labora.com> wrote:
> Hi Gwendal,
>
> On 22/02/18 03:20, Gwendal Grignou wrote:
>> On Mon, Feb 19, 2018 at 2:41 PM, Enric Balletbo i Serra
>> <enric.balletbo@...labora.com> wrote:
>>> From: Gwendal Grignou <gwendal@...omium.org>
>> This patch is not needed anymore. It was added to
>>>
>>> Send dummy command to EC at resume time, wait for status.
>>> If EC loses that command and return a status for the
>>> pre-suspend command, we will not interpret that status as an
>>> answer for an important command.
>>>
>>> Signed-off-by: Gwendal Grignou <gwendal@...omium.org>
>>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
>> Hold on for this commit. We have only used it in 3.14 kernels. It
>> looks like the issue has been addressed by a more elegant solution at
>> https://chromium.googlesource.com/chromiumos/third_party/kernel/+/0225a9de5971b99770344c04e0eba5b35ca68f71
>
> Just to make sure.
>
> I don't see this patch reverted in current chromeos-4.4, seems that both are
> applied. The patch is still there [1]. So, to double check, can I remove this
> patch from this series and add only the one that moves the system sleep pm ops
> to late?
You're right, it is still in chromeos-4.4. If it is still really
needed, we will apply it later.
Thanks,

Gwendal.
>
> [1]
> https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-4.4/drivers/platform/chrome/cros_ec_dev.c#782
>
>>> ---
>>>  drivers/mfd/cros_ec_dev.c | 10 ++++++++++
>>>  1 file changed, 10 insertions(+)
>>>
>>> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
>>> index fc98e0564061..c901839317ae 100644
>>> --- a/drivers/mfd/cros_ec_dev.c
>>> +++ b/drivers/mfd/cros_ec_dev.c
>>> @@ -553,6 +553,16 @@ static __maybe_unused int ec_device_suspend(struct device *dev)
>>>  static __maybe_unused int ec_device_resume(struct device *dev)
>>>  {
>>>         struct cros_ec_dev *ec = dev_get_drvdata(dev);
>>> +       char msg[sizeof(struct ec_response_get_version) +
>>> +                sizeof(CROS_EC_DEV_VERSION)];
>>> +       int ret;
>>> +
>>> +       /* Be sure the communication with the EC is reestablished */
>>> +       ret = ec_get_version(ec, msg, sizeof(msg));
>>> +       if (ret < 0) {
>>> +               dev_err(ec->ec_dev->dev, "No EC response at resume: %d\n", ret);
>>> +               return 0;
>> Besides, that looks wrong, we should try to resume the lightbar.
>>> +       }
>>>
>>>         lb_resume(ec);
>>>
>>> --
>>> 2.16.1
>>>
>
> Thanks,
>   Enric