Re: [PATCH v7 00/16] Intel IPU3 ImgU patchset

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sakari,

On Monday, 3 December 2018 11:51:01 EET Sakari Ailus wrote:
> On Fri, Nov 30, 2018 at 01:07:53AM +0200, Laurent Pinchart wrote:
> > On Wednesday, 7 November 2018 06:16:47 EET Bing Bu Cao wrote:
> >> On 11/01/2018 08:03 PM, Sakari Ailus wrote:
> >>> On Mon, Oct 29, 2018 at 03:22:54PM -0700, Yong Zhi wrote:
> > 
> > [snip]
> > 
> >>>> ImgU media topology print:
> >>>> 
> >>>> # media-ctl -d /dev/media0 -p
> >>>> Media controller API version 4.19.0
> >>>> 
> >>>> Media device information
> >>>> ------------------------
> >>>> driver          ipu3-imgu
> >>>> model           ipu3-imgu
> >>>> serial
> >>>> bus info        PCI:0000:00:05.0
> >>>> hw revision     0x80862015
> >>>> driver version  4.19.0
> >>>> 
> >>>> Device topology
> >>>> - entity 1: ipu3-imgu 0 (5 pads, 5 links)
> >>>>             type V4L2 subdev subtype Unknown flags 0
> >>>>             device node name /dev/v4l-subdev0
> >>>> 	pad0: Sink
> >>>> 		[fmt:UYVY8_2X8/1920x1080 field:none colorspace:unknown
> >>> 
> >>> This doesn't seem right. Which formats can be enumerated from the pad?
> >>> 
> >>>> 		 crop:(0,0)/1920x1080
> >>>> 		 compose:(0,0)/1920x1080]
> >>> 
> >>> Does the compose rectangle affect the scaling on all outputs?
> >> 
> >> Sakari, driver use crop and compose targets to help set input-feeder and
> >> BDS output resolutions which are 2 key block of whole imaging pipeline,
> >> not the actual ending output, but they will impact the final output.
> >> 
> >>>> 		<- "ipu3-imgu 0 input":0 []
> >>> 
> >>> Are there links that have no useful link configuration? If so, you
> >>> should set them enabled and immutable in the driver.
> >> 
> >> The enabled status of input pads is used to get which pipe that user is
> >> trying to enable (ipu3_link_setup()), so it could not been set as
> >> immutable.
> > 
> > Each pipe needs an input in order to operate, so from that point of view
> > the input is mandatory. Why can't we make this link immutable, and use
> > the stream state (VIDIOC_STREAMON/VIDIOC_STREAMOFF) to enable/disable the
> > pipes ?
> 
> There are only two options (AFAIK) in choosing the firmware, and by
> configuring the links this is better visible to the user: the links the
> state of which can be changed are not immutable. The driver can also obtain
> the explicit pipeline configuration, which makes the implementation more
> simple.

Do you mean that different firmwares are loaded based on link configuration ? 
Does it also mean that once we start using the first pipeline the 
configuration of the second pipeline can't be changed anymore ? If so, what's 
the reason for such a limitation ?

-- 
Regards,

Laurent Pinchart