linux-kernel - Re: [PATCH 2/2] media: atmel-isi: move configure_geometry() to start

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Date:	Tue, 4 Aug 2015 14:19:33 +0800
From:	Josh Wu <josh.wu@...el.com>
To:	Laurent Pinchart <laurent.pinchart@...asonboard.com>
CC:	Linux Media Mailing List <linux-media@...r.kernel.org>,
	"Guennadi Liakhovetski" <g.liakhovetski@....de>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] media: atmel-isi: move configure_geometry() to start_streaming()

Hi, Laurent

On 8/3/2015 9:27 PM, Laurent Pinchart wrote:
> Hi Josh,
>
> On Monday 03 August 2015 11:56:01 Josh Wu wrote:
>> On 7/31/2015 10:37 PM, Laurent Pinchart wrote:
>>> On Wednesday 17 June 2015 18:39:39 Josh Wu wrote:
>>>> As in set_fmt() function we only need to know which format is been set,
>>>> we don't need to access the ISI hardware in this moment.
>>>>
>>>> So move the configure_geometry(), which access the ISI hardware, to
>>>> start_streaming() will make code more consistent and simpler.
>>>>
>>>> Signed-off-by: Josh Wu <josh.wu@...el.com>
>>>> ---
>>>>
>>>>    drivers/media/platform/soc_camera/atmel-isi.c | 17 +++++------------
>>>>    1 file changed, 5 insertions(+), 12 deletions(-)
>>>>
>>>> diff --git a/drivers/media/platform/soc_camera/atmel-isi.c
>>>> b/drivers/media/platform/soc_camera/atmel-isi.c index 8bc40ca..b01086d
>>>> 100644
>>>> --- a/drivers/media/platform/soc_camera/atmel-isi.c
>>>> +++ b/drivers/media/platform/soc_camera/atmel-isi.c
>>>> @@ -390,6 +390,11 @@ static int start_streaming(struct vb2_queue *vq,
>>>> unsigned int count) /* Disable all interrupts */
>>>>
>>>>    	isi_writel(isi, ISI_INTDIS, (u32)~0UL);
>>>>
>>>> +	ret = configure_geometry(isi, icd->user_width, icd->user_height,
>>>> +				icd->current_fmt->code);
>>> I would also make configure_geometry a void function, as the only failure
>>> case really can't occur.
>> I think this case can be reached if user require a RGB565 format to
>> capture and sensor also support RGB565 format.
>> As atmel-isi driver will provide RGB565 support via the pass-through
>> mode (maybe we need re-consider this part).
>>
>> So that will cause the configure_geometry() returns an error since it
>> found the bus format is not Y8 or YUV422.
>>
>> In my opinion, we should not change configure_geometry()'s return type,
>> until we add a insanity format check before we call configure_geometry()
>> in future.
> It will really confuse the user if S_FMT accepts a format but STREAMON fails
> due to the format being unsupported. Could that be fixed by defaulting to a
> known supported format in S_FMT if the requested format isn't support ?

yes, it's the right way to go.

> You
> could then remove the error check in configure_geometry().

So I will send a v2 patches, which will add one more patch to add 
insanity check on the S_FMT and remove the error check code in 
configure_geometry().

And for this patch in v2, I will add your reviewed-by tag. Is that Okay 
for you?

Best Regards,
Josh Wu

>>> Apart from that,
>>>
>>> Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
>> Thanks for the review.
>>
>> Best Regards,
>> Josh Wu
>>
>>>> +	if (ret < 0)
>>>> +		return ret;
>>>> +
>>>>
>>>>    	spin_lock_irq(&isi->lock);
>>>>    	/* Clear any pending interrupt */
>>>>    	isi_readl(isi, ISI_STATUS);
>>>>
>>>> @@ -477,8 +482,6 @@ static int isi_camera_init_videobuf(struct vb2_queue
>>>> *q, static int isi_camera_set_fmt(struct soc_camera_device *icd,
>>>>
>>>>    			      struct v4l2_format *f)
>>>>    
>>>>    {
>>>>
>>>> -	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
>>>> -	struct atmel_isi *isi = ici->priv;
>>>>
>>>>    	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
>>>>    	const struct soc_camera_format_xlate *xlate;
>>>>    	struct v4l2_pix_format *pix = &f->fmt.pix;
>>>>
>>>> @@ -511,16 +514,6 @@ static int isi_camera_set_fmt(struct
>>>> soc_camera_device
>>>> *icd, if (mf->code != xlate->code)
>>>>
>>>>    		return -EINVAL;
>>>>
>>>> -	/* Enable PM and peripheral clock before operate isi registers */
>>>> -	pm_runtime_get_sync(ici->v4l2_dev.dev);
>>>> -
>>>> -	ret = configure_geometry(isi, pix->width, pix->height, xlate->code);
>>>> -
>>>> -	pm_runtime_put(ici->v4l2_dev.dev);
>>>> -
>>>> -	if (ret < 0)
>>>> -		return ret;
>>>> -
>>>>
>>>>    	pix->width		= mf->width;
>>>>    	pix->height		= mf->height;
>>>>    	pix->field		= mf->field;

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