linux-kernel - Re: [PATCH v2 1/2] i2c: tegra: Better handle case where CPU0 is busy for a long time

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Date:   Wed, 22 Apr 2020 17:07:26 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Jon Hunter <jonathanh@...dia.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Manikanta Maddireddy <mmaddireddy@...dia.com>,
        Vidya Sagar <vidyas@...dia.com>
Cc:     linux-i2c@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] i2c: tegra: Better handle case where CPU0 is busy
 for a long time

22.04.2020 16:59, Jon Hunter пишет:
> 
> On 22/04/2020 14:40, Dmitry Osipenko wrote:
>> 21.04.2020 22:42, Jon Hunter пишет:
>>>
>>> On 21/04/2020 16:08, Dmitry Osipenko wrote:
>>>> 21.04.2020 17:40, Jon Hunter пишет:
>>>>>
>>>>> On 21/04/2020 14:25, Dmitry Osipenko wrote:
>>>>>> 21.04.2020 12:49, Jon Hunter пишет:
>>>>>> ...
>>>>>>> I can try the above, but I agree it would be best to avoid messing with
>>>>>>> the suspend levels if possible.
>>>>>>
>>>>>> Will be awesome if you could try it and report back the result.
>>>>>>
>>>>>
>>>>> I gave it a try but suspend still fails.
>>>>
>>>> Perhaps the RPM's -EACCES is returned from here:
>>>>
>>>> https://elixir.free-electrons.com/linux/v5.7-rc2/source/drivers/base/power/runtime.c#L723
>>>>
>>>> Which suggests that I2C is accessed after being suspended. I guess the
>>>> PCIe driver suspends after the I2C and somehow my change affected the
>>>> suspension order, although not sure how.
>>>>
>>>> Jon, could you please try to enable PM logging and post the log? Please
>>>> also post log of the working kernel version, so that we could compare
>>>> the PM sequence.
>>>>
>>>> Something like this should enable the logging: "echo 1 >
>>>> /sys/power/pm_trace" + there is RPM tracing.
>>>
>>> Unfortunately, after enabling that I don't any output and so no help there.
>>
>> 1. I now tried to check the pm_trace myself and found that it's
>> available only on X86, my bad.
>>
>> 2. Jon, could you please clarify what exactly you were trying to test?
>>
>> 3. Is it only the Cardhu board that is affected by this problem?
>>
>> 4. Could you please try to add this to the kernel's cmdline and post the
>> logs:
>>
>> tp_printk
>> trace_event=rpm_suspend,rpm_resume,rpm_usage,rpm_idle,rpm_return_int
> 
> 
> So I think that part of the problem already existed prior to these
> patches. Without your patches I see ...
> 
> [   59.543528] tegra-i2c 7000d000.i2c: i2c transfer timed out

Does this I2C timeout happen with my patches? Could you please post full
logs of an older and the recent kernel versions?

> [   59.549036] vdd_sata,avdd_plle: failed to disable
> 
> [   59.553778] Failed to disable avdd-plle: -110
> 
> [   59.558150] tegra-pcie 3000.pcie: failed to disable regulators: -110
> 
> 
> However, now with your patches the i2c is failing to resume and this
> breaks system suspend completely for Tegra30. So far this is the only
> board that appears to break.
> 
> So the above issue needs to be fixed and I will chat to Thierry about this.

Okay