linux-kernel - Re: [PATCH v2 09/20] media: i2c: ov4689: Use runtime PM autosuspend

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Message-ID: <87le7bdsk4.fsf@gmail.com>
Date: Fri, 23 Feb 2024 18:18:12 +0300
From: Mikhail Rudenko <mike.rudenko@...il.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: Sakari Ailus <sakari.ailus@....fi>, linux-media@...r.kernel.org,
 linux-kernel@...r.kernel.org, Laurent Pinchart
 <laurent.pinchart@...asonboard.com>, Jacopo Mondi <jacopo@...ndi.org>,
 Tommaso Merciai <tomm.merciai@...il.com>, Christophe JAILLET
 <christophe.jaillet@...adoo.fr>, Dave Stevenson
 <dave.stevenson@...pberrypi.com>, Mauro Carvalho Chehab
 <mchehab@...nel.org>
Subject: Re: [PATCH v2 09/20] media: i2c: ov4689: Use runtime PM autosuspend


Hi Sakari,

and thanks for the review!

On 2024-02-23 at 08:19 GMT, Sakari Ailus <sakari.ailus@...ux.intel.com> wrote:

> Hi Mikhail,
>
> On Mon, Jan 08, 2024 at 06:06:52PM +0300, Mikhail Rudenko wrote:
>> Hi Sakari,
>>
>> Thanks for the review!
>>
>> On 2024-01-08 at 11:18 GMT, Sakari Ailus <sakari.ailus@....fi> wrote:
>>
>> > Hi Mikhail,
>> >
>> > On Mon, Dec 18, 2023 at 08:40:30PM +0300, Mikhail Rudenko wrote:
>> >> Use runtime PM autosuspend to avoid powering off the sensor during
>> >> fast stop-reconfigure-restart cycles.
>> >>
>> >> Signed-off-by: Mikhail Rudenko <mike.rudenko@...il.com>
>> >> ---
>> >>  drivers/media/i2c/ov4689.c | 22 +++++++++++++++-------
>> >>  1 file changed, 15 insertions(+), 7 deletions(-)
>> >>
>> >> diff --git a/drivers/media/i2c/ov4689.c b/drivers/media/i2c/ov4689.c
>> >> index 5300e621ff90..64cc6d9e48cc 100644
>> >> --- a/drivers/media/i2c/ov4689.c
>> >> +++ b/drivers/media/i2c/ov4689.c
>> >> @@ -407,26 +407,27 @@ static int ov4689_s_stream(struct v4l2_subdev *sd, int on)
>> >>  					  ov4689->cur_mode->num_regs,
>> >>  					  NULL);
>> >>  		if (ret) {
>> >> -			pm_runtime_put(dev);
>> >> +			pm_runtime_put_sync(dev);
>> >
>> > Why are you switching to pm_runtime_put_sync() here? That isn't covered by
>> > the commit message (nor I think should be done).
>>
>> PM autosuspend conversion was suggested earlier by Laurent in his review
>> of this series [1], and he adviced looking at how it was done for the
>> imx290 driver. I followed along the lines of the corresponding patch
>> [2].
>
> There's no need to use the _sync() variant here. And at least it wouldn't
> be related to autosuspend, were you to switch to that.

Ok, will use pm_runtime_put in v3. Or do you suggest dropping this patch
altogether? Laurent?

>>
>> >>  			goto unlock_and_return;
>> >>  		}
>> >>
>> >>  		ret = __v4l2_ctrl_handler_setup(&ov4689->ctrl_handler);
>> >>  		if (ret) {
>> >> -			pm_runtime_put(dev);
>> >> +			pm_runtime_put_sync(dev);
>> >>  			goto unlock_and_return;
>> >>  		}
>> >>
>> >>  		ret = cci_write(ov4689->regmap, OV4689_REG_CTRL_MODE,
>> >>  				OV4689_MODE_STREAMING, NULL);
>> >>  		if (ret) {
>> >> -			pm_runtime_put(dev);
>> >> +			pm_runtime_put_sync(dev);
>> >>  			goto unlock_and_return;
>> >>  		}
>> >>  	} else {
>> >>  		cci_write(ov4689->regmap, OV4689_REG_CTRL_MODE,
>> >>  			  OV4689_MODE_SW_STANDBY, NULL);
>> >> -		pm_runtime_put(dev);
>> >> +		pm_runtime_mark_last_busy(dev);
>> >> +		pm_runtime_put_autosuspend(dev);
>> >>  	}
>> >>
>> >>  unlock_and_return:
>> >> @@ -606,7 +607,9 @@ static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
>> >>  		break;
>> >>  	}
>> >>
>> >> -	pm_runtime_put(dev);
>> >> +	pm_runtime_mark_last_busy(dev);
>> >> +	pm_runtime_put_autosuspend(dev);
>> >
>> > Also note that with runtime PM autosuspend,  you have to use
>> > pm_runtime_get_if_active() instead of pm_runtime_get_if_in_use().
>>
>> Noted, will do so in v3.
>>
>> >> +
>> >>  	return ret;
>> >>  }
>> >>
>> >> @@ -877,8 +880,10 @@ static int ov4689_probe(struct i2c_client *client)
>> >>  	}
>> >>
>> >>  	pm_runtime_set_active(dev);
>> >> +	pm_runtime_get_noresume(dev);
>> >>  	pm_runtime_enable(dev);
>> >> -	pm_runtime_idle(dev);
>> >> +	pm_runtime_set_autosuspend_delay(dev, 1000);
>> >> +	pm_runtime_use_autosuspend(dev);
>> >>
>> >>  	ret = v4l2_async_register_subdev_sensor(sd);
>> >>  	if (ret) {
>> >> @@ -886,11 +891,14 @@ static int ov4689_probe(struct i2c_client *client)
>> >>  		goto err_clean_subdev_pm;
>> >>  	}
>> >>
>> >> +	pm_runtime_mark_last_busy(dev);
>> >> +	pm_runtime_put_autosuspend(dev);
>> >> +
>> >>  	return 0;
>> >>
>> >>  err_clean_subdev_pm:
>> >>  	pm_runtime_disable(dev);
>> >> -	pm_runtime_set_suspended(dev);
>> >> +	pm_runtime_put_noidle(dev);
>> >>  	v4l2_subdev_cleanup(sd);
>> >>  err_clean_entity:
>> >>  	media_entity_cleanup(&sd->entity);
>>
>> [1] https://lore.kernel.org/all/20231211181935.GG27535@pendragon.ideasonboard.com/
>> [2] https://lore.kernel.org/all/20230116144454.1012-14-laurent.pinchart@ideasonboard.com/
>>


--
Best regards,
Mikhail Rudenko