From: Dmitry Osipenko <digetx@gmail.com>
To: Sameer Pujar <spujar@nvidia.com>, Jon Hunter <jonathanh@nvidia.com>
Cc: perex@perex.cz, tiwai@suse.com, robh+dt@kernel.org,
devicetree@vger.kernel.org, alsa-devel@alsa-project.org,
atalambedu@nvidia.com, linux-kernel@vger.kernel.org,
lgirdwood@gmail.com, viswanathl@nvidia.com, sharadg@nvidia.com,
broonie@kernel.org, thierry.reding@gmail.com,
linux-tegra@vger.kernel.org, rlokhande@nvidia.com,
mkumard@nvidia.com, dramesh@nvidia.com
Subject: Re: [alsa-devel] [PATCH 4/9] ASoC: tegra: add Tegra210 based I2S driver
Date: Thu, 23 Jan 2020 18:16:01 +0300 [thread overview]
Message-ID: <b5c581b9-17af-d004-33fb-2cc782ab820a@gmail.com> (raw)
In-Reply-To: <0fc814c2-0dc6-7741-b954-463381ff7fb9@nvidia.com>
23.01.2020 12:22, Sameer Pujar пишет:
>
>
> On 1/22/2020 9:57 PM, Dmitry Osipenko wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> 22.01.2020 14:52, Jon Hunter пишет:
>>> On 22/01/2020 07:16, Sameer Pujar wrote:
>>>
>>> ...
>>>
>>>>>>>>>> +static int tegra210_i2s_remove(struct platform_device *pdev)
>>>>>>>>>> +{
>>>>>>>>>> + pm_runtime_disable(&pdev->dev);
>>>>>>>>>> + if (!pm_runtime_status_suspended(&pdev->dev))
>>>>>>>>>> + tegra210_i2s_runtime_suspend(&pdev->dev);
>>>>>>>>> This breaks device's RPM refcounting if it was disabled in the
>>>>>>>>> active
>>>>>>>>> state. This code should be removed. At most you could warn
>>>>>>>>> about the
>>>>>>>>> unxpected RPM state here, but it shouldn't be necessary.
>>>>>>>> I guess this was added for safety and explicit suspend keeps clock
>>>>>>>> disabled.
>>>>>>>> Not sure if ref-counting of the device matters when runtime PM is
>>>>>>>> disabled and device is removed.
>>>>>>>> I see few drivers using this way.
>>>>>>> It should matter (if I'm not missing something) because RPM should
>>>>>>> be in
>>>>>>> a wrecked state once you'll try to re-load the driver's module.
>>>>>>> Likely
>>>>>>> that those few other drivers are wrong.
>>>>>>>
>>>>>>> [snip]
>>>>>> Once the driver is re-loaded and RPM is enabled, I don't think it
>>>>>> would use
>>>>>> the same 'dev' and the corresponding ref count. Doesn't it use the
>>>>>> new
>>>>>> counters?
>>>>>> If RPM is not working for some reason, most likely it would be the
>>>>>> case
>>>>>> for other
>>>>>> devices. What best driver can do is probably do a force suspend
>>>>>> during
>>>>>> removal if
>>>>>> already not done. I would prefer to keep, since multiple drivers
>>>>>> still
>>>>>> have it,
>>>>>> unless there is a real harm in doing so.
>>>>> I took a closer look and looks like the counter actually should be
>>>>> reset. Still I don't think that it's a good practice to make changes
>>>>> underneath of RPM, it may strike back.
>>>> If RPM is broken, it probably would have been caught during device
>>>> usage.
>>>> I will remove explicit suspend here if no any concerns from other
>>>> folks.
>>>> Thanks.
>>> I recall that this was the preferred way of doing this from the RPM
>>> folks. Tegra30 I2S driver does the same and Stephen had pointed me to
>>> this as a reference.
>>> I believe that this is meant to ensure that the
>>> device is always powered-off regardless of it RPM is enabled or not and
>>> what the current state is.
>> Yes, it was kinda actual for the case of unavailable RPM.
>
>> Anyways, /I think/ variant like this should have been more preferred:
>>
>> if (!pm_runtime_enabled(&pdev->dev))
>> tegra210_i2s_runtime_suspend(&pdev->dev);
>> else
>> pm_runtime_disable(&pdev->dev);
>
> I think it looks to be similar to what is there already.
>
> pm_runtime_disable(&pdev->dev); // it would turn out to be a dummy call
> if !RPM
> if (!pm_runtime_status_suspended(&pdev->dev)) // it is true always if !RPM
> tegra210_i2s_runtime_suspend(&pdev->dev);
Maybe this is fine for !RPM, but not really fine in a case of enabled
RPM. Device could be in resumed state after pm_runtime_disable() if it
wasn't suspended before the disabling.
next prev parent reply other threads:[~2020-01-23 15:16 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-20 14:23 [PATCH 0/9] add ASoC components for AHUB Sameer Pujar
2020-01-20 14:23 ` [PATCH 1/9] dt-bindings: sound: tegra: add DT binding " Sameer Pujar
2020-01-20 14:23 ` [PATCH 2/9] ASoC: tegra: add support for CIF programming Sameer Pujar
2020-01-20 15:58 ` [alsa-devel] " Dmitry Osipenko
2020-01-21 4:41 ` Sameer Pujar
2020-01-21 16:04 ` Dmitry Osipenko
2020-01-27 5:11 ` Sameer Pujar
2020-01-28 22:40 ` Dmitry Osipenko
2020-01-20 14:23 ` [PATCH 3/9] ASoC: tegra: add Tegra210 based DMIC driver Sameer Pujar
2020-01-20 14:23 ` [PATCH 4/9] ASoC: tegra: add Tegra210 based I2S driver Sameer Pujar
2020-01-21 5:15 ` [alsa-devel] " Dmitry Osipenko
2020-01-21 14:21 ` Sameer Pujar
2020-01-21 16:03 ` Dmitry Osipenko
2020-01-22 4:32 ` Sameer Pujar
2020-01-22 6:23 ` Dmitry Osipenko
2020-01-22 7:16 ` Sameer Pujar
2020-01-22 11:52 ` Jon Hunter
2020-01-22 16:27 ` Dmitry Osipenko
2020-01-23 9:22 ` Sameer Pujar
2020-01-23 15:16 ` Dmitry Osipenko [this message]
2020-01-24 9:07 ` Jon Hunter
2020-01-24 9:51 ` Jon Hunter
2020-01-24 14:04 ` Dmitry Osipenko
2020-01-27 5:22 ` Sameer Pujar
2020-01-29 3:41 ` Dmitry Osipenko
2020-02-14 14:05 ` Jon Hunter
2020-02-18 1:00 ` Dmitry Osipenko
2020-02-19 16:10 ` Sameer Pujar
2020-01-22 16:26 ` Dmitry Osipenko
2020-01-20 14:23 ` [PATCH 5/9] ASoC: tegra: add Tegra210 based AHUB driver Sameer Pujar
2020-01-24 1:18 ` [alsa-devel] " Dmitry Osipenko
2020-01-24 3:39 ` Sameer Pujar
2020-01-24 4:28 ` Dmitry Osipenko
2020-01-27 9:45 ` Jon Hunter
2020-01-20 14:23 ` [PATCH 6/9] ASoC: tegra: add Tegra186 based DSPK driver Sameer Pujar
2020-01-20 14:23 ` [PATCH 7/9] ASoC: tegra: add Tegra210 based ADMAIF driver Sameer Pujar
2020-01-24 1:28 ` [alsa-devel] " Dmitry Osipenko
2020-01-24 3:27 ` Sameer Pujar
2020-01-24 4:25 ` Dmitry Osipenko
2020-01-27 5:08 ` Sameer Pujar
2020-01-20 14:23 ` [PATCH 8/9] arm64: tegra: add AHUB components for few Tegra chips Sameer Pujar
2020-01-20 14:23 ` [PATCH 9/9] arm64: tegra: enable AHUB modules " Sameer Pujar
2020-01-28 10:49 ` [PATCH 0/9] add ASoC components for AHUB Sameer Pujar
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