On 10/21/19 10:21 AM, Hans Verkuil wrote:
> On 10/20/19 7:39 PM, Laurent Pinchart wrote:
>> Hi Hans,
>> On Sun, Oct 20, 2019 at 07:26:20PM +0200, Hans Verkuil wrote:
>>> On 10/20/19 7:35 AM, Laurent Pinchart wrote:
>>>> On Sat, Oct 19, 2019 at 11:14:03AM -0500, Adam Ford wrote:
>>>>> On Fri, Oct 18, 2019 at 4:17 PM Sakari Ailus <sakari.ai...@iki.fi> wrote:
>>>>>> On Fri, Oct 18, 2019 at 04:10:23PM -0500, Adam Ford wrote:
>>>>>>> On Fri, Oct 18, 2019 at 4:00 PM Sakari Ailus <sakari.ai...@iki.fi> 
>>>>>>> wrote:
>>>>>>>> On Fri, Oct 18, 2019 at 02:38:57PM -0500, Adam Ford wrote:
>>>>>>>>> I have a DM3730 with a parallel mt9p031 sensor attached.  I am trying
>>>>>>>>> to troubleshoot some issues with streaming video with G-streamer, but
>>>>>>>>> I I think the issue is in how the ISP driver reports the video info.
>>>>>>>>> I have the pipeline to grab from the resizer:
>>>>>>>>> media-ctl -v -V '"mt9p031 1-0048":0 [SGRBG8 1280x720
>>>>>>>>> (664,541)/1280x720], "OMAP3 ISP CCDC":2 [SGRBG8 1280x720], "OMAP3 ISP
>>>>>>>>> preview":1 [UYVY 1280x720], "OMAP3 ISP resizer":1 [UYVY 480x272]'
>>>>>>>>> This make /dev/video6 the output of the resizer and shows the format
>>>>>>>>> and resolution of the output of the resizer as:
>>>>>>>>>      Setting up format UYVY8_1X16 480x272 on pad OMAP3 ISP resizer/1
>>>>>>>>>      Format set: UYVY8_1X16 480x272
>>>>>>>>> I used 480x272 because it's the resolution of my LCD, and I was hoping
>>>>>>>>> the resizer would be able to scale this so the ARM would not need to
>>>>>>>>> do the work, and it appears to not have any issues with this
>>>>>>>>> resolution.
>>>>>>>>> However, if I query the video format, I don't get UYVY:
>>>>>>>>> # v4l2-ctl  -d6 --list-formats-ext
>>>>>>>>> ioctl: VIDIOC_ENUM_FMT
>>>>>>>>>         Type: Video Capture
>>>>>>>>>         [0]: 'RGB3' (RGB3, emulated)
>>>>>>>>>         [1]: 'BGR3' (BGR3, emulated)
>>>>>>>>>         [2]: 'YU12' (YU12, emulated)
>>>>>>>>>         [3]: 'YV12' (YV12, emulated)
>>>>>>>>> This becomes an issue when I attempt to stream video from my camera to
>>>>>>>>> anything, include fake sink:
>>>>>>>>> gst-launch-1.0 -v v4l2src device=/dev/video6 ! fakesink
>>>>>>>>> Tried to capture in RGB3, but device returned format UYVY
>>>>>>>>> So for some reason, when queried, it reports different values than
>>>>>>>>> UYVY, but when attempting to set the video capture to the listed
>>>>>>>>> formats, it returns an error.
>>>>>>>>> gst-launch-1.0 -v v4l2src device=/dev/video6 ! video/x-raw,
>>>>>>>>> format=UYVY ! fakesink
>>>>>>>> I don't have any experience on v4l2src recently but I can comment on 
>>>>>>>> the
>>>>>>>> omap3isp driver.
>>>>>>>> In general, the format the omap3isp may produce on a given video node
>>>>>>>> depends on the format of data which the block associated with the video
>>>>>>>> node is fed with.
>>>>>>>> For instance, in case of the raw Bayer formats, the pixel order does 
>>>>>>>> not
>>>>>>>> change, and thus the pixel order remains all the way from the sensor 
>>>>>>>> to the
>>>>>>>> video node.
>>>>>>> From what I can tell, it looks like the output of the resizer is only
>>>>>>> capable of two formats,
>>>>>>> from ispresizer.c:
>>>>>>>      /* resizer pixel formats */
>>>>>>>      static const unsigned int resizer_formats[] = {
>>>>>>>      MEDIA_BUS_FMT_UYVY8_1X16,
>>>>>>>      MEDIA_BUS_FMT_YUYV8_1X16,
>>>>>>>      };
>>>>>>> Also:
>>>>>>>  * resizer_try_format - Handle try format by pad subdev method
>>>>>>>  * @res   : ISP resizer device
>>>>>>>  * @cfg: V4L2 subdev pad configuration
>>>>>>>  * @pad   : pad num
>>>>>>>  * @fmt   : pointer to v4l2 format structure
>>>>>>>  * @which : wanted subdev format
>>>>>>> switch (pad) {
>>>>>>> case RESZ_PAD_SINK:
>>>>>>>      if (fmt->code != MEDIA_BUS_FMT_YUYV8_1X16 &&
>>>>>>>          fmt->code != MEDIA_BUS_FMT_UYVY8_1X16)
>>>>>>>               fmt->code = MEDIA_BUS_FMT_YUYV8_1X16;
>>>>>>> So it looks to me like if we're trying to do anything other than
>>>>>>> either of those,we set it to MEDIA_BUS_FMT_YUYV8_1X16
>>>>>>> Am I missing something?
>>>>>> I guess for this particular video node there's no need for V4L2 
>>>>>> extensions
>>>>>> to implement ENUM_FMT. Ideally the other nodes would support ENUM_FMT 
>>>>>> that
>>>>>> could provide meaningful information as well.
>>>>> I applied a variation of the patch in question, and I was able to both
>>>>> successfully use g-streamer-1.0 and I was able to see UYVY appear in
>>>>> the list.  in fact, G-Streamer-1.0 was faster than FFPEG with less
>>>>> lag.
>>>>> ioctl: VIDIOC_ENUM_FMT
>>>>>         Type: Video Capture
>>>>>         [0]: 'UYVY' (UYVY 4:2:2)
>>>>>         [1]: 'RGB3' (RGB3, emulated)
>>>>>         [2]: 'BGR3' (BGR3, emulated)
>>>>>         [3]: 'YU12' (YU12, emulated)
>>>>>         [4]: 'YV12' (YV12, emulated)
>>>>> I don't know enough about VL2.  It looks like all the V4L stuff is in
>>>>> the common isp files and not unique to the preview output, resizer
>>>>> output or the CCDC output.  I don't have a CSI camera, so I cannot
>>>>> test anything.
>>>>> I checked all the video outputs, and they are all showing the same
>>>>> information.  I realize the patch I found won't be accepted upstream
>>>>> as-is, but it would be nice to have some mechanism in place that can
>>>>> determine which output node is being used and somehow return the
>>>>> correct data for each node.
>>>>> I would like to do something to help improve this driver and/or make
>>>>> it more compatible with some of the V4L tools (like G-Streamer), so if
>>>>> someone has a recommendation on how we could move forward, I'm willing
>>>>> work on it.
>>>> While I'm not totally opposed to implementing VIDIOC_ENUM_FMT for the
>>>> resizer video node, I'm not sure it would be the best solution to your
>>>> problem. Sure, it will fix an existing issue, but we already know that
>>>> it won't scale, as the other video nodes can't be supported the same
>>>> way.
>>>> So far, our position was mostly that userspace should grow support for
>>>> MC-based devices where VIDIOC_ENUM_FMT isn't implemented. Maybe I'm
>>> Well, I disagree: implementing G/S/TRY_FMT without ENUM_FMT is out-of-spec.
>>> The v4l2-compliance utility would flunk any driver that tries that.
>>> Unfortunately, v4l2-compliance didn't exist (or was in its infancy) when
>>> omap3isp was written.
>> We've never agreed :-)
>>> I didn't even know that ENUM_FMT wasn't implemented for the omap3 ISP.
>>> It makes no sense either: the driver is smart enough to validate the
>>> pixelformat, but not smart enough to be able to enumerate the list of
>>> valid formats for the current pipeline configuration?
>> That's not the problem, the issue is that for MC-enabled drivers subdevs
>> and video nodes are configured in isolation of each other. You thus
>> can't enumerate formats on a video node *for the current pipeline
>> configuration* as there's no such thing, we have no global "test"
>> pipeline configuration. Enumerating formats for the active configuration
>> is possible, but that will confuse userspace even more, as most
>> applications enumerate formats first and then decide how to configure
>> the device based on what is supported.
> So it is OK not to provide ANY information about supported formats and just
> leave it to userspace to guess? I'm happy to just say that ENUM_FMT enumerates
> all supported formats (and allowing them to be rejected if they do not work
> with the actual pipeline), that's already FAR better than not enumerating
> anything at all.
> It's insane that this is apparently still not sorted so long after this driver
> was merged.
>>> I suspect that omap3isp can use some TLC, and this would be one of the
>>> things that need addressing.
>> We need to address this issue in the V4L2 spec first and decide, once
>> and for all, what set of ioctls MC-based drivers need to support, and
>> how they should support them. There's little point in sending patches
>> for the driver until we agree on the spec.
> Well, make an RFC. Seriously. How can you even write libcamera without this
> being sorted?
> Fix this!
> I strongly recommend that you look at Boris' RFC v3 
> (https://patchwork.linuxtv.org/cover/59345/)
> that will be the main discussion during the 'Future work' session in Lyon,
> and post an RFC this week with a suggestion on how to integrate this into
> a new API.
> It is unlikely that this can be integrated into the existing VIDIOC_ENUM_FMT
> since while there are reserved fields, there is no requirement for userspace
> to zero them. They can only be used to return information from the driver.
> (Sorry Sakari, your proposal to use a reserved field for the mediabus format
> won't work).
> So the best ENUM_FMT can do for these drivers is to enumerate all supported
> pixelformats, but without any information on the mediabus formats they can
> be used with.

Posted a proposal for a new EXT_ENUM_FMT here:




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