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Date:   Thu, 16 May 2019 16:35:40 +0000
From:   "Robert R. Howell" <RHowell@...o.edu>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
CC:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Kai-Heng Feng <kai.heng.feng@...onical.com>,
        "lenb@...nel.org" <lenb@...nel.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI / LPSS: Don't skip late system PM ops for hibernate
 on BYT/CHT

Hi Rafael


On 5/16/19 5:11 AM, Rafael J. Wysocki wrote:

> On Thursday, April 25, 2019 6:38:34 PM CEST Robert R. Howell wrote:
>> On 4/24/19 1:20 AM, Rafael J. Wysocki wrote:
>>
>>> On Tue, Apr 23, 2019 at 10:03 PM Robert R. Howell <RHowell@...o.edu> wrote:
>>>>
>>>> On 4/23/19 2:07 AM, Rafael J. Wysocki wrote:
>>>>>
>>>>> On Sat, Apr 20, 2019 at 12:44 AM Robert R. Howell <RHowell@...o.edu> wrote:
>>>>>>
>>>>>> On 4/18/19 5:42 AM, Hans de Goede wrote:
>>>>>>
>>>>>>>> On 4/8/19 2:16 AM, Hans de Goede wrote:>
>>>>>>>>>
>>>>>>>>> Hmm, interesting so you have hibernation working on a T100TA
>>>>>>>>> (with 5.0 + 02e45646d53b reverted), right ?
>>>>>>>>>
>>>>>>
>>>>>>
>>>>>> I've managed to find a way around the i2c_designware timeout issues
>>>>>> on the T100TA's.  The key is to NOT set DPM_FLAG_SMART_SUSPEND,
>>>>>> which was added in the 02e45646d53b commit.
>>>>>>
>>>>>> To test that I've started with a 5.1-rc5 kernel, applied your recent patch
>>>>>> to acpi_lpss.c, then apply the following patch of mine, removing
>>>>>> DPM_FLAG_SMART_SUSPEND.  (For the T100 hardware I need to apply some
>>>>>> other patches as well but those are not related to the i2c-designware or
>>>>>> acpi issues addressed here.)
>>>>>>
>>>>>> On a resume from hibernation I still see one error:
>>>>>>   "i2c_designware 80860F41:00: Error i2c_dw_xfer called while suspended"
>>>>>> but I no longer get the i2c_designware timeouts, and audio does now work
>>>>>> after the resume.
>>>>>>
>>>>>> Removing DPM_FLAG_SMART_SUSPEND may not be what you want for other
>>>>>> hardware, but perhaps this will give you a clue as to what is going
>>>>>> wrong with hibernate/resume on the T100TA's.
>>>>>
>>>>> What if you drop DPM_FLAG_LEAVE_SUSPENDED alone instead?
>>>>>
>>>>
>>>> I did try dropping just DPM_FLAG_LEAVE_SUSPENDED, dropping just
>>>> DPM_FLAG_SMART_SUSPEND, and dropping both flags.  When I just drop
>>>> DPM_FLAG_LEAVE_SUSPENDED I still get the i2c_designware timeouts
>>>> after the resume.  If I drop just DPM_FLAG_SMART_SUSPEND or drop both,
>>>> then the timeouts go away.
>>>
>>> OK, thanks!
>>>
>>> Is non-hibernation system suspend affected too?
>>
>> I just ran some tests on a T100TA, using the 5.1-rc5 code with Hans' patch applied
>> but without any changes to i2c-designware-platdrv.c, so the
>> DPM_FLAG_SMART_PREPARE, DPM_FLAG_SMART_SUSPEND, and DPM_FLAG_LEAVE_SUSPENDED flags
>> are all set.
>>
>> Suspend does work OK, and after resume I do NOT get any of the crippling
>> i2c_designware timeout errors which cause sound to fail after hibernate.  I DO see one
>>   "i2c_designware 80860F41:00: Error i2c_dw_xfer call while suspended"
>> error on resume, just as I do on hibernate.  I've attached a portion of dmesg below.
>> The "asus_wmi:  Unknown key 79 pressed" error is a glitch which occurs
>> intermittently on these machines, but doesn't seem related to the other issues.
>> I had one test run when it was absent but the rest of the messages were the
>> same -- but then kept getting that unknown key error on all my later tries.
>>
>> I did notice the "2sidle" in the following rather than "shallow" or "deep".  A
>> cat of /sys/power/state shows "freeze mem disk" but a
>> cat of /sys/power/mem_sleep" shows only "[s2idle] so it looks like shallow and deep
>> are not enabled for this system.  I did check the input power (or really current)
>> as it went into suspend and the micro-usb power input drops from about
>> 0.5 amps to 0.05 amps.  But clearly a lot of devices are still active, as movement
>> of a bluetooth mouse (the MX Anywhere 2) will wake it from suspend.  That presumably is
>> why suspend doesn't trigger the same i2c_designware problems as hibernate.
>>
>> Let me know if I can do any other tests.
> 
> Can you please check if the appended patch makes the hibernate issue go away for you, without any other changes?
> 
> ---
>  drivers/pci/pci-driver.c |   36 ++++++++++--------------------------
>  1 file changed, 10 insertions(+), 26 deletions(-)
> 
> Index: linux-pm/drivers/pci/pci-driver.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-driver.c
> +++ linux-pm/drivers/pci/pci-driver.c
> @@ -957,15 +957,14 @@ static int pci_pm_freeze(struct device *
>         }
> 
>         /*
> -        * This used to be done in pci_pm_prepare() for all devices and some
> -        * drivers may depend on it, so do it here.  Ideally, runtime-suspended
> -        * devices should not be touched during freeze/thaw transitions,
> -        * however.
> +        * Resume all runtime-suspended devices before creating a snapshot
> +        * image of system memory, because the restore kernel generally cannot
> +        * be expected to always handle them consistently and pci_pm_restore()
> +        * always leaves them as "active", so ensure that the state saved in the
> +        * image will always be consistent with that.
>          */
> -       if (!dev_pm_smart_suspend_and_suspended(dev)) {
> -               pm_runtime_resume(dev);
> -               pci_dev->state_saved = false;
> -       }
> +       pm_runtime_resume(dev);
> +       pci_dev->state_saved = false;
> 
>         if (pm->freeze) {
>                 int error;
> @@ -992,9 +991,6 @@ static int pci_pm_freeze_noirq(struct de
>         struct pci_dev *pci_dev = to_pci_dev(dev);
>         struct device_driver *drv = dev->driver;
> 
> -       if (dev_pm_smart_suspend_and_suspended(dev))
> -               return 0;
> -
>         if (pci_has_legacy_pm_support(pci_dev))
>                 return pci_legacy_suspend_late(dev, PMSG_FREEZE);
> 
> @@ -1024,16 +1020,6 @@ static int pci_pm_thaw_noirq(struct devi
>         struct device_driver *drv = dev->driver;
>         int error = 0;
> 
> -       /*
> -        * If the device is in runtime suspend, the code below may not work
> -        * correctly with it, so skip that code and make the PM core skip all of
> -        * the subsequent "thaw" callbacks for the device.
> -        */
> -       if (dev_pm_smart_suspend_and_suspended(dev)) {
> -               dev_pm_skip_next_resume_phases(dev);
> -               return 0;
> -       }
> -
>         if (pcibios_pm_ops.thaw_noirq) {
>                 error = pcibios_pm_ops.thaw_noirq(dev);
>                 if (error)
> @@ -1093,8 +1079,10 @@ static int pci_pm_poweroff(struct device
> 
>         /* The reason to do that is the same as in pci_pm_suspend(). */
>         if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
> -           !pci_dev_keep_suspended(pci_dev))
> +           !pci_dev_keep_suspended(pci_dev)) {
>                 pm_runtime_resume(dev);
> +               pci_dev->state_saved = false;
> +       }
> 
>         pci_dev->state_saved = false;
>         if (pm->poweroff) {
> @@ -1168,10 +1156,6 @@ static int pci_pm_restore_noirq(struct d
>         struct device_driver *drv = dev->driver;
>         int error = 0;
> 
> -       /* This is analogous to the pci_pm_resume_noirq() case. */
> -       if (dev_pm_smart_suspend_and_suspended(dev))
> -               pm_runtime_set_active(dev);
> -
>         if (pcibios_pm_ops.restore_noirq) {
>                 error = pcibios_pm_ops.restore_noirq(dev);
>                 if (error)
> 
> 
> 

Thanks for the patch.  I'm traveling right now so I'm away from the machines I need to test this, 
but I'll be back home by the end of the week and will test the patch then.

Bob Howell

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