linux-samsung-soc.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jonathan Bakker <xc-racer2@live.ca>
To: Sylwester Nawrocki <s.nawrocki@samsung.com>,
	Tomasz Figa <tfiga@chromium.org>
Cc: kyungmin.park@samsung.com, mchehab@kernel.org, kgene@kernel.org,
	krzk@kernel.org, linux-media@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 03/11] media: exynos4-is: Fix nullptr when no CSIS device present
Date: Sat, 11 Jul 2020 09:27:07 -0700	[thread overview]
Message-ID: <BN6PR04MB066001C2B9BB205A634FC6A8A3620@BN6PR04MB0660.namprd04.prod.outlook.com> (raw)
In-Reply-To: <854c0c60-b239-6626-2423-47058cb58feb@samsung.com>

Hi Sylwester and Tomasz,

On 2020-07-08 8:11 a.m., Sylwester Nawrocki wrote:
> Hi,
> 
> On 07.07.2020 19:55, Tomasz Figa wrote:
>> On Sat, Apr 25, 2020 at 07:26:42PM -0700, Jonathan Bakker wrote:
>>> Not all devices use the CSIS device, some may use the FIMC directly in
>>> which case the CSIS device isn't registered.  This leads to a nullptr
>>> exception when starting the stream as the CSIS device is always
>>> referenced.  Instead, if getting the CSIS device fails, try getting the
>>> FIMC directly to check if we are using the subdev API
>>>
>>> Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>
>>> ---
>>>  drivers/media/platform/exynos4-is/media-dev.c | 17 ++++++++++++++++-
>>>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
>> Thank you for the patch. Please see my comments inline.
> 

Thank you both for taking the time to review the patches.

>>> diff --git a/drivers/media/platform/exynos4-is/media-dev.c b/drivers/media/platform/exynos4-is/media-dev.c
>>> index 9aaf3b8060d5..5c32abc7251b 100644
>>> --- a/drivers/media/platform/exynos4-is/media-dev.c
>>> +++ b/drivers/media/platform/exynos4-is/media-dev.c
>>> @@ -289,11 +289,26 @@ static int __fimc_pipeline_s_stream(struct exynos_media_pipeline *ep, bool on)
>>>  		{ IDX_CSIS, IDX_FLITE, IDX_FIMC, IDX_SENSOR, IDX_IS_ISP },
>>>  	};
>>>  	struct fimc_pipeline *p = to_fimc_pipeline(ep);
>>> -	struct fimc_md *fmd = entity_to_fimc_mdev(&p->subdevs[IDX_CSIS]->entity);
>>>  	enum fimc_subdev_index sd_id;
>>>  	int i, ret = 0;
>>>  
>>>  	if (p->subdevs[IDX_SENSOR] == NULL) {
>>> +		struct fimc_md *fmd;
>>> +		struct v4l2_subdev *sd = p->subdevs[IDX_CSIS];
>>> +
>>> +		if (!sd)
>>> +			sd = p->subdevs[IDX_FIMC];
>>> +
>>> +		if (!sd) {
>>> +			/*
>>> +			 * If neither CSIS nor FIMC was set up,
>>> +			 * it's impossible to have any sensors
>>> +			 */
>>> +			return -ENODEV;
>>> +		}
>>> +
>>> +		fmd = entity_to_fimc_mdev(&sd->entity);
>>> +
>>
>> Are you sure this is the correct thing to do here? In general, the media
>> controller should be instantiated only if there are sensors in the system.
> 
> The code being changed is only about getting a pointer to the driver private 
> data structure 'struct fimc_md', for that we need to get hold of a media 
> entity that represents a subdev that is actually available in the pipeline.
> In original code it is overlooked that there might camera pipelines without
> the CSIS subdev. 
> 
>> What do you mean by using "the FIMC directly"? Do you mean using it only as
>> an m2m image processor or with a sensor, but without the CSIS, which would
>> be the case for parallel I/F sensors?
> 
> I think it is about a use case where the sensor is connected directly to the 
> FIMC capture interface (parallel), without the MIPI-CSI2 receiverin between.
> 

Yep, that's exactly what I mean.  The device that I'm working with (first gen
Galaxy S) has two devices (S5KA3DFX and CE147) connected via parallel input
to Camera Port A (yes, both of them to the same port).

Is it more correct to say "using the parallel port instead of the CSIS device"?
I'm happy to reword the commit message if that is the case.  

>> Could you point me to the place where CSIS is always dereferenced? A quick
>> look through the code only revealed that everywhere it seems to be guarded
>> by a NULL check.
> 
> It's in this patch, above, the very first line that the patch removes.
> 

Exactly :)

>> Another thought from looking at the implementation of
>> __fimc_pipeline_s_stream() is that it probably shouldn't call s_stream on
>> all the subdevices included in seq[], but only on those that are actually
>> included as a part of the pipeline. It would be quite a waste of power to
>> enable unnecessary hardware.
> 
> As we talked on IRC, only subdev in current active media pipeline will be
> powered on/off. The p->subdevs[] array is sparsely populated and there is 
> a test for NULL in __subdev_set_power(). Perhaps the test should be moved
> to the caller instead (fimc_pipeline_s_power()), so we don't ignore any
> ENXIO errors from the s_power v4l2_subdev_call. But is a material for 
> a separate patch.
> 

Ok, I'll leave it be for now.

Thanks,
Jonathan

  reply	other threads:[~2020-07-11 16:27 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200426022650.10355-1-xc-racer2@live.ca>
2020-04-26  2:26 ` [PATCH 01/11] media: exynos4-is: Remove static driver data for S5PV210 FIMC variants Jonathan Bakker
2020-07-07 17:33   ` Tomasz Figa
2020-07-08 14:45   ` Sylwester Nawrocki
2020-04-26  2:26 ` [PATCH 02/11] media: exynos4-is: Request syscon only if ISP writeback is present Jonathan Bakker
2020-07-07 17:34   ` Tomasz Figa
2020-07-08 14:47   ` Sylwester Nawrocki
2020-04-26  2:26 ` [PATCH 03/11] media: exynos4-is: Fix nullptr when no CSIS device present Jonathan Bakker
2020-07-07 17:55   ` Tomasz Figa
2020-07-08 15:11     ` Sylwester Nawrocki
2020-07-11 16:27       ` Jonathan Bakker [this message]
2020-07-08 14:49   ` Sylwester Nawrocki
2020-04-26  2:26 ` [PATCH 04/11] media: exynos4-is: Correct missing entity function initialization Jonathan Bakker
2020-07-07 18:09   ` Tomasz Figa
2020-07-08 15:34     ` Sylwester Nawrocki
2020-07-11 16:35       ` Jonathan Bakker
2020-04-26  2:26 ` [PATCH 05/11] media: exynos4-is: Improve support for sensors with multiple pads Jonathan Bakker
2020-07-07 18:13   ` Tomasz Figa
2020-07-11 18:21     ` Jonathan Bakker
2020-04-26  2:26 ` [PATCH 06/11] media: exynos4-is: Properly set JPEG options when not using CSIS Jonathan Bakker
2020-07-07 18:23   ` Tomasz Figa
2020-07-08 15:45     ` Sylwester Nawrocki
2020-07-11 16:43       ` Jonathan Bakker
2020-07-08 15:46   ` Sylwester Nawrocki
2020-04-26  2:26 ` [PATCH 07/11] media: exynos4-is: Add support for multiple sensors on one port Jonathan Bakker
2020-07-07 18:36   ` Tomasz Figa
2020-07-11 16:48     ` Jonathan Bakker
2020-04-26  2:26 ` [PATCH 08/11] media: exynos4-is: Remove inh_sensor_ctrls Jonathan Bakker
2020-07-07 18:37   ` Tomasz Figa
2020-07-08 15:47   ` Sylwester Nawrocki
2020-04-26  2:26 ` [PATCH 09/11] media: exynos4-is: Remove unused struct member input_index Jonathan Bakker
2020-07-07 18:38   ` Tomasz Figa
2020-07-08 15:49   ` Sylwester Nawrocki
2020-04-26  2:26 ` [PATCH 10/11] media: exynos4-is: Prevent duplicate call to media_pipeline_stop Jonathan Bakker
2020-07-07 18:44   ` Tomasz Figa
2020-07-11 18:17     ` Jonathan Bakker
2020-07-20 13:10       ` Tomasz Figa
2020-07-24 23:46         ` Jonathan Bakker
2020-07-27 13:48           ` Tomasz Figa
2020-04-26  2:26 ` [PATCH 11/11] media: exynos4-is: Correct parallel port probing Jonathan Bakker
2020-07-07 18:48   ` Tomasz Figa
2020-07-08 16:15   ` Sylwester Nawrocki
2020-07-11 18:18     ` Jonathan Bakker

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=BN6PR04MB066001C2B9BB205A634FC6A8A3620@BN6PR04MB0660.namprd04.prod.outlook.com \
    --to=xc-racer2@live.ca \
    --cc=kgene@kernel.org \
    --cc=krzk@kernel.org \
    --cc=kyungmin.park@samsung.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=mchehab@kernel.org \
    --cc=s.nawrocki@samsung.com \
    --cc=tfiga@chromium.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).