Re: [PATCH v3 14/17] media: i2c: imx290: Initialize runtime PM before subdev - Linux regression tracking (Thorsten Leemhuis)

From: "Linux regression tracking (Thorsten Leemhuis)" <regressions@leemhuis.info>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Linux regressions mailing list <regressions@lists.linux.dev>
Cc: linux-media@vger.kernel.org, Sakari Ailus <sakari.ailus@iki.fi>,
	Manivannan Sadhasivam <mani@kernel.org>,
	Alexander Stein <alexander.stein@ew.tq-group.com>,
	Dave Stevenson <dave.stevenson@raspberrypi.com>,
	Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH v3 14/17] media: i2c: imx290: Initialize runtime PM before subdev
Date: Sun, 12 Mar 2023 14:59:59 +0100	[thread overview]
Message-ID: <79488ad7-5709-235b-14b4-1518e989c7a3@leemhuis.info> (raw)
In-Reply-To: <20230312133435.GI2545@pendragon.ideasonboard.com>

On 12.03.23 14:34, Laurent Pinchart wrote:
> On Sun, Mar 12, 2023 at 02:10:16PM +0100, Linux regression tracking (Thorsten Leemhuis) wrote:
>> On 27.02.23 18:52, Guenter Roeck wrote:
>>> On Mon, Jan 16, 2023 at 04:44:51PM +0200, Laurent Pinchart wrote:
>>>> Initializing the subdev before runtime PM means that no subdev
>>>> initialization can interact with the runtime PM framework. This can be
>>>> problematic when modifying controls, as the .s_ctrl() handler commonly
>>>> calls pm_runtime_get_if_in_use(). These code paths are not trivial,
>>>> making the driver fragile and possibly causing subtle bugs.
>>>>
>>>> To make the subdev initialization more robust, initialize runtime PM
>>>> first.
>>>>
>>>> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>>> Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com>
>>>> ---
>>>
>>> This patch results in
>>>
>>> Error log:
>>> <stdin>:1517:2: warning: #warning syscall clone3 not implemented [-Wcpp]
>>> drivers/media/i2c/imx290.c:1090:12: error: 'imx290_runtime_suspend' defined but not used [-Werror=unused-function]
>>>  1090 | static int imx290_runtime_suspend(struct device *dev)
>>>       |            ^~~~~~~~~~~~~~~~~~~~~~
>>> drivers/media/i2c/imx290.c:1082:12: error: 'imx290_runtime_resume' defined but not used [-Werror=unused-function]
>>>  1082 | static int imx290_runtime_resume(struct device *dev)
>>>
>>> if PM runtime support is disabled( alpha:allmodconfig, csky:allmodconfig,
>>> and others).
>>
>> Looks like Guenter never got a reply, but from a recent kernelci report
>> it looks like above warning still happens:
>> https://lore.kernel.org/all/640bceb7.a70a0220.af8cd.146b@mx.google.com/
>>
>> Laurent, do you still have it on your radar?
> 
> I don't. Arnd has sent a fix
> (https://lore.kernel.org/linux-media/20230207161316.293923-1-arnd@kernel.org),
> I've reviewed it, now I expect Sakari to pick it up and get it upstream.

Ahh, great, thx for taking the time and letting me know, much appreciated.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
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If I did something stupid, please tell me, as explained on that page.

P.S.: update the status

#regzbot monitor:
https://lore.kernel.org/linux-media/20230207161316.293923-1-arnd@kernel.org/
#regzbot fix: media: i2c: imx290: fix conditional function defintions
#regzbot ignore-activity