Re: [RFC] SUBDEV_S/G_SELECTION IOCTLs
Hi Sakari, On Saturday 26 November 2011 10:25:19 Sakari Ailus wrote: > Laurent Pinchart wrote: > > On Thursday 10 November 2011 23:29:34 Sakari Ailus wrote: > >> On Thu, Nov 10, 2011 at 04:23:19PM +0100, Tomasz Stanislawski wrote: > >>> On 11/08/2011 10:55 PM, Sakari Ailus wrote: [snip] > A sensor > > > The intent is to obtain a VGA image from a 8 MP sensor which provides > following pipeline: > > pixel_array:0 [crop] ---> 0:binner:1 ---> [crop] 0:scaler:1 [crop] > > Binner is an entity which can perform scaling, but only in factor of > 1/n, where n is a positive integer. No cropping is needed. The intent > is to get a 640x480 image from such sensor. (This doesn't involve any > other configuration as the image size related one.) > > The initial state of the pipeline > > pixel_array:0 binner:0binner:1scaler:0scaler:1 > > compose > (0,0)/3600x2464 (0,0)/3600x2464 (0,0)/3600x2464 (0,0)/3600x2464 (0,0)/ > 3 600x2464 > crop (0,0)/3600x2464 (0,0)/3600x2464 (0,0)/3600x2464 (0,0)/3600x2464 > ( > 0 ,0)/3600x2464 fmt 3600x2464 3600x2464 3600x2464 > 3600x2464 3600x2464 > > This will configure the binning on the binner subdev sink pad: > > SUBDEV_S_SELECTION(binner:0, COMPOSE_ACTIVE, (0,0)/1800x1232); > > pixel_array:0 binner:0binner:1scaler:0scaler:1 > > compose > (0,0)/3600x2464 (0,0)/1800x1232 (0,0)/1800x1232 (0,0)/3600x2464 (0,0)/ > 3 600x2464 > crop (0,0)/3600x2464 (0,0)/3600x2464 (0,0)/1800x1232 (0,0)/3600x2464 > ( > 0 ,0)/3600x2464 fmt 3600x2464 3600x2464 1800x1232 > 3600x2464 3600x2464 > > The same format must be set on the scaler pad 0 as well. This will > reset the size inside the scaler to a sane default, which is no > scaling: > > SUBDEV_S_FMT(scaler:0, 1800x1232); > > pixel_array:0 binner:0binner:1scaler:0scaler:1 > > compose > (0,0)/3600x2464 (0,0)/1800x1232 (0,0)/1800x1232 (0,0)/1800x1232 (0,0)/ > 1 800x1232 > crop (0,0)/3600x2464 (0,0)/3600x2464 (0,0)/1800x1232 (0,0)/1800x1232 > ( > 0 ,0)/1800x1232 fmt 3600x2464 3600x2464 1800x1232 > 1800x1232 1800x1232 > >>> > >>> I assume that scaler can upscale image 1800x1232 on scaler:0 to > >>> 3600x2464 on pad scaler:1. Therefore the format and compose targets > >>> on scaler:1 should not be changed. > >> > >> Open question one: do we need a flag for other than s_selection to not > >> to reset the following stages? > >> > >> That said, we also need to define a behaviour for that: if changes must > >> be made e.g. to crop and compose rectangle on both sink and source > >> pads, then how are they made? > > > > Shouldn't that be left to the drivers to decide ? Different devices will > > likely have different requirements. > > That's quite possible, but still there should be a general rule that > should be obeyed if possible, or if it makes sense; hopefully both. > > I think that enabling the keep-pipeline bit should tell that the changes > should be propagated as little as possible while not making too smart > decisions. The expected behaviour should be defined. Shouldn't the keep-pipeline bit prevent any propagation ? > Say, if one has configured crop and scaling on the sink pad, how does > the change of the sink pad format affect the two? > > How about this: as the sink format still consists of the whole image, > the crop rectangle should be scaled (by the driver) to fit to the new > image and the scaling factor should be adjusted so that result after > scaling in the sink pad changes as little as possible. There still may > be changes to the image size after scaling depending on the properties > of the hardware. > > Do you think that would that make sense? I think we should make it simpler. What about just setting all rectangles downstream to the same size as the sink format ? That's if the keep-pipeline bit isn't set, if it's set modifying the sink format should probably be disallowed. > To perform further scaling on the scaler, the COMPOSE target is used > on the scaler subdev's SOURCE pad: > > SUBDEV_S_SELECTION(scaler:0, COMPOSE_ACTIVE, (0,0)/640x480); > > pixel_array:0 binner:0binner:1scaler:0scaler:1 > > compose > (0,0)/3600x2464 (0,0)/1800x1232 (0,0)/1800x1232 (0,0)/640x480 > > > > (0,0)/640 > > > x480 > crop (0,0)/3600x2464 (0,0)/3600x2464 (0,0)/1800x1232 (0,0)/1800x1232 > ( > 0 ,0)/640x480 fmt3600x2464 3600x2464 1800x1232 > 1800x1232 640x480 > >>> > >>> It is possible to compose 640x480 image into 1800
Re: [RFC] SUBDEV_S/G_SELECTION IOCTLs
Laurent Pinchart wrote: > Hi Sakari, Hi Laurent, > On Thursday 10 November 2011 23:29:34 Sakari Ailus wrote: >> On Thu, Nov 10, 2011 at 04:23:19PM +0100, Tomasz Stanislawski wrote: >>> On 11/08/2011 10:55 PM, Sakari Ailus wrote: Hi all, This RFC discusses the SUBDEV_S_SELECTION/SUBDEV_G_SELECTION API which is intended to amend and replace the existing SUBDEV_[SG]_CROP API. These IOCTLs have previously been discussed in the Cambridge V4L2 brainstorming meeting [0] and their intent is to provide more configurability for subdevs, including cropping on the source pads and composing for a display. The S_SELECTION patches for V4L2 nodes are available here [1] and the existing documentation for the V4L2 subdev pad format configuration can be found in [2]. SUBDEV_[SG]_SELECTION is intended to fully replace SUBDEV_[SG]_CROP in drivers as the latter can be implemented in SUBDEV_[SG]_SELECTION using active CROP target on sink pads. That can be done in v4l2-ioctl.c so drivers only will need to implement SUBDEV_[SG]_SELECTION. Questions, comments and thoughts are welcome, especially regarding new use cases. Order of configuration == >>> >>> Sorry, what is exactly the SOURCE pad and SINK pad? The spec says >>> "Data flows from a source pad to a sink pad.". Does in refer to a >>> subdev or to a link? Look at the image below: >>> >>> data link0 --> (pad0) [subdev] (pad1) > link1 >>> >>> From subdev's point of view, pad0 is data source, pad1 is the sink. >>> From link0's point of view, pad0 is a data sink. Which >>> interpretation is correct? >> >> It should say "link" in the spec. That needs to be clarified in the spec... >> The proposed order of the subdev configuration is as follows. Individual steps may be omitted since any of the steps will reset the rectangles / sizes for any following step. >>> >>> I assume that SOURCE and SINK are defined from the link's point of >>> view. Otherwise it would mean that configuration goes in order >>> opposite to data flow order. >>> >>> I do not think that resetting is a good idea. It is better to state >>> in spec that change of a given target guarantee that targets/formats >>> earlier in pipeline are not modified. Part below pipeline may change >>> or not. The application should check if the configuration of lower >>> parts of pipeline is suitable. For example >> >> I don't think the above text in the RFC would be a change on how it works >> at the moment. Inside a subdev the following stages of configuration (as >> in the flow of data) are indeed reset. > > Nit-picking here, I wouldn't talk about resetting but about propagating. > > Changing a rectangle should be guaranteed not to change any other rectangle > "upstream" in the pipeline, and may modify rectangles "downstream" (limited to > the same subdev) as required by format propagation. A flag is required to > allow/prevent propagation. > > I don't think there's any disagreement here though, my understanding is that > we all agree to this. I'd think so, too, but it's still good to specify that. I'll change the term I use in the next version. >> Much of the hardware actually needs this unless they're scalers. >> >>> Change of COMPOSE target on SINK pad must not modify >>> - format on the SINK pad >>> - CROP on the SINK pad >>> >>> All other parameters may change. Of course the configuration of >>> lower part must be consistent with higher part of the pipeline. >> >> The above two would not be changed since they are before the compose window >> in the sink pad. >> >> If the user wishes the following stages also not to be modified, (s)he can >> specify it using a flag. We could call it V4L2_SUBDEV_SEL_FLAG_LOCALCHANGE. >> Better names are always welcome. :) >> >> See also open question 1. >> 1. SUBDEV_S_FMT on the SINK pad. The user will issue SUBDEV_S_FMT to set the subdev sink pad image size and media bus format code and other parameters in v4l2_mbus_framefmt as necessary. 2. SUBDEV_S_SELECTION with CROP target on the SINK pad. The crop rectangle is set related to the image size given in step 1). 3. SUBDEV_S_SELECTION with COMPOSE target on the SINK pad. The size of the compose rectangle, if it differs from the size of the rectangle given in 2), signifies user's wish to perform scaling. 4. SUBDEV_S_SELECTION with CROP target on the SOURCE pad. Configure cropping performed by the subdev after scaling. 5. SUBDEV_S_SELECTION with COMPOSE target on the SOURCE pad. This configures composition on the display if relevant for the subdevice. (In this case the COMPOSE bounds will yield to the size of the display.) 6. SUBDEV_S_FMT on the SOURCE pad. The size of the image is defined by setting CROP on the SOURCE pad, so SUBDEV_S_FMT only has an effect of cha
Re: [RFC] SUBDEV_S/G_SELECTION IOCTLs
Hi Sakari, On Thursday 10 November 2011 23:29:34 Sakari Ailus wrote: > On Thu, Nov 10, 2011 at 04:23:19PM +0100, Tomasz Stanislawski wrote: > > On 11/08/2011 10:55 PM, Sakari Ailus wrote: > > >Hi all, > > > > > >This RFC discusses the SUBDEV_S_SELECTION/SUBDEV_G_SELECTION API which > > >is intended to amend and replace the existing SUBDEV_[SG]_CROP API. > > >These IOCTLs have previously been discussed in the Cambridge V4L2 > > >brainstorming meeting [0] and their intent is to provide more > > >configurability for subdevs, including cropping on the source pads and > > >composing for a display. > > > > > >The S_SELECTION patches for V4L2 nodes are available here [1] and the > > >existing documentation for the V4L2 subdev pad format configuration can > > >be found in [2]. > > > > > >SUBDEV_[SG]_SELECTION is intended to fully replace SUBDEV_[SG]_CROP in > > >drivers as the latter can be implemented in SUBDEV_[SG]_SELECTION using > > >active CROP target on sink pads. That can be done in v4l2-ioctl.c so > > >drivers only will need to implement SUBDEV_[SG]_SELECTION. > > > > > > > > >Questions, comments and thoughts are welcome, especially regarding new > > >use cases. > > > > > > > > >Order of configuration > > >== > > > > Sorry, what is exactly the SOURCE pad and SINK pad? The spec says > > "Data flows from a source pad to a sink pad.". Does in refer to a > > subdev or to a link? Look at the image below: > > > > data link0 --> (pad0) [subdev] (pad1) > link1 > > > > From subdev's point of view, pad0 is data source, pad1 is the sink. > > From link0's point of view, pad0 is a data sink. Which > > interpretation is correct? > > It should say "link" in the spec. That needs to be clarified in the spec... > > > >The proposed order of the subdev configuration is as follows. Individual > > >steps may be omitted since any of the steps will reset the rectangles / > > >sizes for any following step. > > > > I assume that SOURCE and SINK are defined from the link's point of > > view. Otherwise it would mean that configuration goes in order > > opposite to data flow order. > > > > I do not think that resetting is a good idea. It is better to state > > in spec that change of a given target guarantee that targets/formats > > earlier in pipeline are not modified. Part below pipeline may change > > or not. The application should check if the configuration of lower > > parts of pipeline is suitable. For example > > I don't think the above text in the RFC would be a change on how it works > at the moment. Inside a subdev the following stages of configuration (as > in the flow of data) are indeed reset. Nit-picking here, I wouldn't talk about resetting but about propagating. Changing a rectangle should be guaranteed not to change any other rectangle "upstream" in the pipeline, and may modify rectangles "downstream" (limited to the same subdev) as required by format propagation. A flag is required to allow/prevent propagation. I don't think there's any disagreement here though, my understanding is that we all agree to this. > Much of the hardware actually needs this unless they're scalers. > > > Change of COMPOSE target on SINK pad must not modify > > - format on the SINK pad > > - CROP on the SINK pad > > > > All other parameters may change. Of course the configuration of > > lower part must be consistent with higher part of the pipeline. > > The above two would not be changed since they are before the compose window > in the sink pad. > > If the user wishes the following stages also not to be modified, (s)he can > specify it using a flag. We could call it V4L2_SUBDEV_SEL_FLAG_LOCALCHANGE. > Better names are always welcome. :) > > See also open question 1. > > > >1. SUBDEV_S_FMT on the SINK pad. The user will issue SUBDEV_S_FMT to set > > >the subdev sink pad image size and media bus format code and other > > >parameters in v4l2_mbus_framefmt as necessary. > > > > > >2. SUBDEV_S_SELECTION with CROP target on the SINK pad. The crop > > >rectangle is set related to the image size given in step 1). > > > > > >3. SUBDEV_S_SELECTION with COMPOSE target on the SINK pad. The size of > > >the compose rectangle, if it differs from the size of the rectangle > > >given in 2), signifies user's wish to perform scaling. > > > > > >4. SUBDEV_S_SELECTION with CROP target on the SOURCE pad. Configure > > >cropping performed by the subdev after scaling. > > > > > >5. SUBDEV_S_SELECTION with COMPOSE target on the SOURCE pad. This > > >configures composition on the display if relevant for the subdevice. > > >(In this case the COMPOSE bounds will yield to the size of the > > >display.) > > > > > >6. SUBDEV_S_FMT on the SOURCE pad. The size of the image is defined by > > >setting CROP on the SOURCE pad, so SUBDEV_S_FMT only has an effect of > > >changing other parameters than size. > > > > > >As defined in [2], when performing any of the configuration phases > > >above, the formats and selections are res
Re: [RFC] SUBDEV_S/G_SELECTION IOCTLs
Hi Sakari,
It looks nice trial for setting the image and stream size.
I'm curious just one thing. Does it help to use the way setting size "easily"?
The most media drivers has its own negotiation way, and at every time using
such media drivers, the application developers should learn the way to be
negotiated. They generally wants the size which they want, not to be
negotiated.
But, this new API looks to fix the sizes, to be able to make negotiation codes
easy, "not to negotiate".
So, in such meaning, how about your thoughts? Does it help the user to handle
the size more easily?
Regards,
Heungjun Kim
2011. 11. 9. 오전 6:55 Sakari Ailus 작성:
> Hi all,
>
> This RFC discusses the SUBDEV_S_SELECTION/SUBDEV_G_SELECTION API which is
> intended to amend and replace the existing SUBDEV_[SG]_CROP API. These
> IOCTLs have previously been discussed in the Cambridge V4L2 brainstorming
> meeting [0] and their intent is to provide more configurability for subdevs,
> including cropping on the source pads and composing for a display.
>
> The S_SELECTION patches for V4L2 nodes are available here [1] and the
> existing documentation for the V4L2 subdev pad format configuration can be
> found in [2].
>
> SUBDEV_[SG]_SELECTION is intended to fully replace SUBDEV_[SG]_CROP in
> drivers as the latter can be implemented in SUBDEV_[SG]_SELECTION using
> active CROP target on sink pads. That can be done in v4l2-ioctl.c so drivers
> only will need to implement SUBDEV_[SG]_SELECTION.
>
>
> Questions, comments and thoughts are welcome, especially regarding new use
> cases.
>
>
> Order of configuration
> ==
>
> The proposed order of the subdev configuration is as follows. Individual
> steps may be omitted since any of the steps will reset the rectangles /
> sizes for any following step.
>
> 1. SUBDEV_S_FMT on the SINK pad. The user will issue SUBDEV_S_FMT to set the
> subdev sink pad image size and media bus format code and other parameters in
> v4l2_mbus_framefmt as necessary.
>
> 2. SUBDEV_S_SELECTION with CROP target on the SINK pad. The crop rectangle
> is set related to the image size given in step 1).
>
> 3. SUBDEV_S_SELECTION with COMPOSE target on the SINK pad. The size of the
> compose rectangle, if it differs from the size of the rectangle given in 2),
> signifies user's wish to perform scaling.
>
> 4. SUBDEV_S_SELECTION with CROP target on the SOURCE pad. Configure cropping
> performed by the subdev after scaling.
>
> 5. SUBDEV_S_SELECTION with COMPOSE target on the SOURCE pad. This configures
> composition on the display if relevant for the subdevice. (In this case the
> COMPOSE bounds will yield to the size of the display.)
>
> 6. SUBDEV_S_FMT on the SOURCE pad. The size of the image is defined by
> setting CROP on the SOURCE pad, so SUBDEV_S_FMT only has an effect of
> changing other parameters than size.
>
> As defined in [2], when performing any of the configuration phases above,
> the formats and selections are reset to defaults from each phase onwards.
> For example, SUBDEV_S_SELECTION with CROP target on the SINK pad will
> --- beyond its obvious function of setting CROP selection target on the SINK
> pad --- reset the COMPOSE selection target on SINK pad, as well as the CROP
> selection target and format on the SOURCE pad.
>
>
> Definitions
> ===
>
> /**
> * struct v4l2_subdev_selection - selection info
> *
> * @which: either V4L2_SUBDEV_FORMAT_ACTIVE or V4L2_SUBDEV_FORMAT_TRY
> * @pad: pad number, as reported by the media API
> * @target: selection target, used to choose one of possible rectangles
> * @flags: constraints flags
> * @r: coordinates of selection window
> * @reserved: for future use, rounds structure size to 64 bytes, set to zero
> *
> * Hardware may use multiple helper window to process a video stream.
> * The structure is used to exchange this selection areas between
> * an application and a driver.
> */
> struct v4l2_subdev_selection {
>__u32 which;
>__u32 pad;
>__u32 target;
>__u32 flags;
>struct v4l2_rect r;
>__u32 reserved[8];
> };
>
> Both SUBDEV_S_SELECTION and SUBDEV_G_SELECTION would take struct
> v4l2_subdev_selection as the IOCTL argument (RW).
>
> The same target definitions and flags apply as in [1], with possible
> exception of the PADDED targets --- see below. The flags will gain _SUBDEV
> prefix after the existing V4L2 prefix.
>
>
> Sample use cases
>
>
>
> OMAP 3 ISP preview
> --
>
> The OMAP 3 ISP preview block provides cropping on preview sink pad, but also
> horizontal averaging. The horizontal averaging may scale the image
> horizontally by factor 1/n, where n is either 1, 2, 4 or 8.
>
> The preview block also performs pixel format conversion from raw bayer to
> YUV. Other image processing operations crops maximum of 12 columns and 8 rows
> before the format conversion. After the format conversion, further 2 columns
> are cropped.
>
> To make this easy for th
Re: [RFC] SUBDEV_S/G_SELECTION IOCTLs
Hi Tomasz, Thanks for your comments! On Thu, Nov 10, 2011 at 04:23:19PM +0100, Tomasz Stanislawski wrote: > Hi Sakari, > > > On 11/08/2011 10:55 PM, Sakari Ailus wrote: > >Hi all, > > > >This RFC discusses the SUBDEV_S_SELECTION/SUBDEV_G_SELECTION API which is > >intended to amend and replace the existing SUBDEV_[SG]_CROP API. These > >IOCTLs have previously been discussed in the Cambridge V4L2 brainstorming > >meeting [0] and their intent is to provide more configurability for subdevs, > >including cropping on the source pads and composing for a display. > > > >The S_SELECTION patches for V4L2 nodes are available here [1] and the > >existing documentation for the V4L2 subdev pad format configuration can be > >found in [2]. > > > >SUBDEV_[SG]_SELECTION is intended to fully replace SUBDEV_[SG]_CROP in > >drivers as the latter can be implemented in SUBDEV_[SG]_SELECTION using > >active CROP target on sink pads. That can be done in v4l2-ioctl.c so drivers > >only will need to implement SUBDEV_[SG]_SELECTION. > > > > > >Questions, comments and thoughts are welcome, especially regarding new use > >cases. > > > > > >Order of configuration > >== > > Sorry, what is exactly the SOURCE pad and SINK pad? The spec says > "Data flows from a source pad to a sink pad.". Does in refer to a > subdev or to a link? Look at the image below: > > data link0 --> (pad0) [subdev] (pad1) > link1 > > From subdev's point of view, pad0 is data source, pad1 is the sink. > From link0's point of view, pad0 is a data sink. Which > interpretation is correct? It should say "link" in the spec. That needs to be clarified in the spec... > >The proposed order of the subdev configuration is as follows. Individual > >steps may be omitted since any of the steps will reset the rectangles / > >sizes for any following step. > > I assume that SOURCE and SINK are defined from the link's point of > view. Otherwise it would mean that configuration goes in order > opposite to data flow order. > > I do not think that resetting is a good idea. It is better to state > in spec that change of a given target guarantee that targets/formats > earlier in pipeline are not modified. Part below pipeline may change > or not. The application should check if the configuration of lower > parts of pipeline is suitable. For example I don't think the above text in the RFC would be a change on how it works at the moment. Inside a subdev the following stages of configuration (as in the flow of data) are indeed reset. Much of the hardware actually needs this unless they're scalers. > Change of COMPOSE target on SINK pad must not modify > - format on the SINK pad > - CROP on the SINK pad > > All other parameters may change. Of course the configuration of > lower part must be consistent with higher part of the pipeline. The above two would not be changed since they are before the compose window in the sink pad. If the user wishes the following stages also not to be modified, (s)he can specify it using a flag. We could call it V4L2_SUBDEV_SEL_FLAG_LOCALCHANGE. Better names are always welcome. :) See also open question 1. > > > >1. SUBDEV_S_FMT on the SINK pad. The user will issue SUBDEV_S_FMT to set the > >subdev sink pad image size and media bus format code and other parameters in > >v4l2_mbus_framefmt as necessary. > > > >2. SUBDEV_S_SELECTION with CROP target on the SINK pad. The crop rectangle > >is set related to the image size given in step 1). > > > >3. SUBDEV_S_SELECTION with COMPOSE target on the SINK pad. The size of the > >compose rectangle, if it differs from the size of the rectangle given in 2), > >signifies user's wish to perform scaling. > > > >4. SUBDEV_S_SELECTION with CROP target on the SOURCE pad. Configure cropping > >performed by the subdev after scaling. > > > >5. SUBDEV_S_SELECTION with COMPOSE target on the SOURCE pad. This configures > >composition on the display if relevant for the subdevice. (In this case the > >COMPOSE bounds will yield to the size of the display.) > > > >6. SUBDEV_S_FMT on the SOURCE pad. The size of the image is defined by > >setting CROP on the SOURCE pad, so SUBDEV_S_FMT only has an effect of > >changing other parameters than size. > > > >As defined in [2], when performing any of the configuration phases above, > >the formats and selections are reset to defaults from each phase onwards. > >For example, SUBDEV_S_SELECTION with CROP target on the SINK pad will > >--- beyond its obvious function of setting CROP selection target on the SINK > >pad --- reset the COMPOSE selection target on SINK pad, as well as the CROP > >selection target and format on the SOURCE pad. > > > > > > I think that formal definitions of CROP,COMPOSE for pads are needed. > As I remember from Cambridge brainstorming we agreed that > SINK.COMPOSE and SOURCE.CROP are expressed in subdev's internal > coordinate system. > The SINK.CROP is expressed in link0's coordinate system and > SOURCE.COMPOSE is expressed in li
Re: [RFC] SUBDEV_S/G_SELECTION IOCTLs
Hi Sylwester, Thanks for the comments! On Thu, Nov 10, 2011 at 12:57:10PM +0100, Sylwester Nawrocki wrote: > Hi Sakari, > > On 11/08/2011 10:55 PM, Sakari Ailus wrote: > > Hi all, > > > > This RFC discusses the SUBDEV_S_SELECTION/SUBDEV_G_SELECTION API which is > > intended to amend and replace the existing SUBDEV_[SG]_CROP API. These > > IOCTLs have previously been discussed in the Cambridge V4L2 brainstorming > > meeting [0] and their intent is to provide more configurability for subdevs, > > including cropping on the source pads and composing for a display. > > > > The S_SELECTION patches for V4L2 nodes are available here [1] and the > > existing documentation for the V4L2 subdev pad format configuration can be > > found in [2]. > > > > SUBDEV_[SG]_SELECTION is intended to fully replace SUBDEV_[SG]_CROP in > > drivers as the latter can be implemented in SUBDEV_[SG]_SELECTION using > > active CROP target on sink pads. That can be done in v4l2-ioctl.c so drivers > > only will need to implement SUBDEV_[SG]_SELECTION. > > > > > > Questions, comments and thoughts are welcome, especially regarding new use > > cases. > > > > > > Order of configuration > > == > > > > The proposed order of the subdev configuration is as follows. Individual > > steps may be omitted since any of the steps will reset the rectangles / > > sizes for any following step. > > > > 1. SUBDEV_S_FMT on the SINK pad. The user will issue SUBDEV_S_FMT to set the > > subdev sink pad image size and media bus format code and other parameters in > > v4l2_mbus_framefmt as necessary. > > > > 2. SUBDEV_S_SELECTION with CROP target on the SINK pad. The crop rectangle > > is set related to the image size given in step 1). > > > > 3. SUBDEV_S_SELECTION with COMPOSE target on the SINK pad. The size of the > > compose rectangle, if it differs from the size of the rectangle given in 2), > > signifies user's wish to perform scaling. > > > > 4. SUBDEV_S_SELECTION with CROP target on the SOURCE pad. Configure cropping > > performed by the subdev after scaling. > > > > 5. SUBDEV_S_SELECTION with COMPOSE target on the SOURCE pad. This configures > > composition on the display if relevant for the subdevice. (In this case the > > COMPOSE bounds will yield to the size of the display.) > > > > 6. SUBDEV_S_FMT on the SOURCE pad. The size of the image is defined by > > setting CROP on the SOURCE pad, so SUBDEV_S_FMT only has an effect of > > changing other parameters than size. > > > > As defined in [2], when performing any of the configuration phases above, > > the formats and selections are reset to defaults from each phase onwards. > > For example, SUBDEV_S_SELECTION with CROP target on the SINK pad will > > --- beyond its obvious function of setting CROP selection target on the SINK > > pad --- reset the COMPOSE selection target on SINK pad, as well as the CROP > > selection target and format on the SOURCE pad. > > I thought we agreed that the spec will not be enforcing resetting parameters > to defaults from each phase onwards. Also I couldn't find anything explicitly > telling this in [2]. Let's consider simple use case: video pipeline with image > sensor, scaler, composer and DMA engine. > Initially user performs the configuration in the above described order. > Then video stream is started and user wants to change the area cropped at > image sensor, which will then appear in the configured compose window. We > assume > the H/W supports changing crop window position during streaming. > > We can't reset existing configuration below/after CROP phase at the scaler > sink > pad, because we want the compose window unchanged. > > I guess this is where we need the flag to disable propagating the > configuration > inside single subdev, don't we ? Yes, the intent is to define one. See open question number 1. I think a note of the behaviour must be added to the spec. It might have been left open on purpose since no consensus had been reached on how to best handle it. I'll make the needed changes to the next version of the RFC. > > [snip] > > > Open questions > > == > > > > 1. Keep subdev configuration flag. In Cambourne meeting the case of the OMAP > > 3 ISP resizer configuration dilemma was discussed, and the proposal was to > > add a flag to disable propagating the configuration inside a single subdev. > > Propagating inside a single subdev is the default. Where do we need this > > flag; is just SUBDEV_S_SELECTION enough? [0] > > > > 2. Are PADDED targets relevant for media bus formats? [3] > > > > > > References > > == > > > > [0] http://www.mail-archive.com/linux-media@vger.kernel.org/msg35361.html > > > > [1] http://www.mail-archive.com/linux-media@vger.kernel.org/msg36206.html > > > > [2] http://hverkuil.home.xs4all.nl/spec/media.html#subdev > > > > [3] http://www.mail-archive.com/linux-media@vger.kernel.org/msg36203.html > > --- > Regards, > Sylwester -- Sakari Ailus e-mail: sakari.
Re: [RFC] SUBDEV_S/G_SELECTION IOCTLs
Hi Sakari,
On 11/08/2011 10:55 PM, Sakari Ailus wrote:
Hi all,
This RFC discusses the SUBDEV_S_SELECTION/SUBDEV_G_SELECTION API which is
intended to amend and replace the existing SUBDEV_[SG]_CROP API. These
IOCTLs have previously been discussed in the Cambridge V4L2 brainstorming
meeting [0] and their intent is to provide more configurability for subdevs,
including cropping on the source pads and composing for a display.
The S_SELECTION patches for V4L2 nodes are available here [1] and the
existing documentation for the V4L2 subdev pad format configuration can be
found in [2].
SUBDEV_[SG]_SELECTION is intended to fully replace SUBDEV_[SG]_CROP in
drivers as the latter can be implemented in SUBDEV_[SG]_SELECTION using
active CROP target on sink pads. That can be done in v4l2-ioctl.c so drivers
only will need to implement SUBDEV_[SG]_SELECTION.
Questions, comments and thoughts are welcome, especially regarding new use
cases.
Order of configuration
==
Sorry, what is exactly the SOURCE pad and SINK pad? The spec says "Data
flows from a source pad to a sink pad.". Does in refer to a subdev or to
a link? Look at the image below:
data link0 --> (pad0) [subdev] (pad1) > link1
From subdev's point of view, pad0 is data source, pad1 is the sink.
From link0's point of view, pad0 is a data sink. Which interpretation
is correct?
The proposed order of the subdev configuration is as follows. Individual
steps may be omitted since any of the steps will reset the rectangles /
sizes for any following step.
I assume that SOURCE and SINK are defined from the link's point of view.
Otherwise it would mean that configuration goes in order opposite to
data flow order.
I do not think that resetting is a good idea. It is better to state in
spec that change of a given target guarantee that targets/formats
earlier in pipeline are not modified. Part below pipeline may change or
not. The application should check if the configuration of lower parts of
pipeline is suitable. For example
Change of COMPOSE target on SINK pad must not modify
- format on the SINK pad
- CROP on the SINK pad
All other parameters may change. Of course the configuration of lower
part must be consistent with higher part of the pipeline.
1. SUBDEV_S_FMT on the SINK pad. The user will issue SUBDEV_S_FMT to set the
subdev sink pad image size and media bus format code and other parameters in
v4l2_mbus_framefmt as necessary.
2. SUBDEV_S_SELECTION with CROP target on the SINK pad. The crop rectangle
is set related to the image size given in step 1).
3. SUBDEV_S_SELECTION with COMPOSE target on the SINK pad. The size of the
compose rectangle, if it differs from the size of the rectangle given in 2),
signifies user's wish to perform scaling.
4. SUBDEV_S_SELECTION with CROP target on the SOURCE pad. Configure cropping
performed by the subdev after scaling.
5. SUBDEV_S_SELECTION with COMPOSE target on the SOURCE pad. This configures
composition on the display if relevant for the subdevice. (In this case the
COMPOSE bounds will yield to the size of the display.)
6. SUBDEV_S_FMT on the SOURCE pad. The size of the image is defined by
setting CROP on the SOURCE pad, so SUBDEV_S_FMT only has an effect of
changing other parameters than size.
As defined in [2], when performing any of the configuration phases above,
the formats and selections are reset to defaults from each phase onwards.
For example, SUBDEV_S_SELECTION with CROP target on the SINK pad will
--- beyond its obvious function of setting CROP selection target on the SINK
pad --- reset the COMPOSE selection target on SINK pad, as well as the CROP
selection target and format on the SOURCE pad.
I think that formal definitions of CROP,COMPOSE for pads are needed.
As I remember from Cambridge brainstorming we agreed that SINK.COMPOSE
and SOURCE.CROP are expressed in subdev's internal coordinate system.
The SINK.CROP is expressed in link0's coordinate system and
SOURCE.COMPOSE is expressed in link1's coordinate system.
Definitions
===
/**
* struct v4l2_subdev_selection - selection info
*
* @which: either V4L2_SUBDEV_FORMAT_ACTIVE or V4L2_SUBDEV_FORMAT_TRY
* @pad: pad number, as reported by the media API
* @target: selection target, used to choose one of possible rectangles
* @flags: constraints flags
* @r: coordinates of selection window
* @reserved: for future use, rounds structure size to 64 bytes, set to zero
*
* Hardware may use multiple helper window to process a video stream.
* The structure is used to exchange this selection areas between
* an application and a driver.
*/
struct v4l2_subdev_selection {
__u32 which;
__u32 pad;
__u32 target;
__u32 flags;
struct v4l2_rect r;
__u32 reserved[8];
};
Both SUBDEV_S_SELECTION and SUBDEV_G_SELECTION would take struct
v4l2_subdev_selection as the IOCTL argument (RW).
The same target definitions and flags apply as
Re: [RFC] SUBDEV_S/G_SELECTION IOCTLs
Hi Sakari, On 11/08/2011 10:55 PM, Sakari Ailus wrote: > Hi all, > > This RFC discusses the SUBDEV_S_SELECTION/SUBDEV_G_SELECTION API which is > intended to amend and replace the existing SUBDEV_[SG]_CROP API. These > IOCTLs have previously been discussed in the Cambridge V4L2 brainstorming > meeting [0] and their intent is to provide more configurability for subdevs, > including cropping on the source pads and composing for a display. > > The S_SELECTION patches for V4L2 nodes are available here [1] and the > existing documentation for the V4L2 subdev pad format configuration can be > found in [2]. > > SUBDEV_[SG]_SELECTION is intended to fully replace SUBDEV_[SG]_CROP in > drivers as the latter can be implemented in SUBDEV_[SG]_SELECTION using > active CROP target on sink pads. That can be done in v4l2-ioctl.c so drivers > only will need to implement SUBDEV_[SG]_SELECTION. > > > Questions, comments and thoughts are welcome, especially regarding new use > cases. > > > Order of configuration > == > > The proposed order of the subdev configuration is as follows. Individual > steps may be omitted since any of the steps will reset the rectangles / > sizes for any following step. > > 1. SUBDEV_S_FMT on the SINK pad. The user will issue SUBDEV_S_FMT to set the > subdev sink pad image size and media bus format code and other parameters in > v4l2_mbus_framefmt as necessary. > > 2. SUBDEV_S_SELECTION with CROP target on the SINK pad. The crop rectangle > is set related to the image size given in step 1). > > 3. SUBDEV_S_SELECTION with COMPOSE target on the SINK pad. The size of the > compose rectangle, if it differs from the size of the rectangle given in 2), > signifies user's wish to perform scaling. > > 4. SUBDEV_S_SELECTION with CROP target on the SOURCE pad. Configure cropping > performed by the subdev after scaling. > > 5. SUBDEV_S_SELECTION with COMPOSE target on the SOURCE pad. This configures > composition on the display if relevant for the subdevice. (In this case the > COMPOSE bounds will yield to the size of the display.) > > 6. SUBDEV_S_FMT on the SOURCE pad. The size of the image is defined by > setting CROP on the SOURCE pad, so SUBDEV_S_FMT only has an effect of > changing other parameters than size. > > As defined in [2], when performing any of the configuration phases above, > the formats and selections are reset to defaults from each phase onwards. > For example, SUBDEV_S_SELECTION with CROP target on the SINK pad will > --- beyond its obvious function of setting CROP selection target on the SINK > pad --- reset the COMPOSE selection target on SINK pad, as well as the CROP > selection target and format on the SOURCE pad. I thought we agreed that the spec will not be enforcing resetting parameters to defaults from each phase onwards. Also I couldn't find anything explicitly telling this in [2]. Let's consider simple use case: video pipeline with image sensor, scaler, composer and DMA engine. Initially user performs the configuration in the above described order. Then video stream is started and user wants to change the area cropped at image sensor, which will then appear in the configured compose window. We assume the H/W supports changing crop window position during streaming. We can't reset existing configuration below/after CROP phase at the scaler sink pad, because we want the compose window unchanged. I guess this is where we need the flag to disable propagating the configuration inside single subdev, don't we ? [snip] > Open questions > == > > 1. Keep subdev configuration flag. In Cambourne meeting the case of the OMAP > 3 ISP resizer configuration dilemma was discussed, and the proposal was to > add a flag to disable propagating the configuration inside a single subdev. > Propagating inside a single subdev is the default. Where do we need this > flag; is just SUBDEV_S_SELECTION enough? [0] > > 2. Are PADDED targets relevant for media bus formats? [3] > > > References > == > > [0] http://www.mail-archive.com/linux-media@vger.kernel.org/msg35361.html > > [1] http://www.mail-archive.com/linux-media@vger.kernel.org/msg36206.html > > [2] http://hverkuil.home.xs4all.nl/spec/media.html#subdev > > [3] http://www.mail-archive.com/linux-media@vger.kernel.org/msg36203.html --- Regards, Sylwester -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[RFC] SUBDEV_S/G_SELECTION IOCTLs
Hi all,
This RFC discusses the SUBDEV_S_SELECTION/SUBDEV_G_SELECTION API which is
intended to amend and replace the existing SUBDEV_[SG]_CROP API. These
IOCTLs have previously been discussed in the Cambridge V4L2 brainstorming
meeting [0] and their intent is to provide more configurability for subdevs,
including cropping on the source pads and composing for a display.
The S_SELECTION patches for V4L2 nodes are available here [1] and the
existing documentation for the V4L2 subdev pad format configuration can be
found in [2].
SUBDEV_[SG]_SELECTION is intended to fully replace SUBDEV_[SG]_CROP in
drivers as the latter can be implemented in SUBDEV_[SG]_SELECTION using
active CROP target on sink pads. That can be done in v4l2-ioctl.c so drivers
only will need to implement SUBDEV_[SG]_SELECTION.
Questions, comments and thoughts are welcome, especially regarding new use
cases.
Order of configuration
==
The proposed order of the subdev configuration is as follows. Individual
steps may be omitted since any of the steps will reset the rectangles /
sizes for any following step.
1. SUBDEV_S_FMT on the SINK pad. The user will issue SUBDEV_S_FMT to set the
subdev sink pad image size and media bus format code and other parameters in
v4l2_mbus_framefmt as necessary.
2. SUBDEV_S_SELECTION with CROP target on the SINK pad. The crop rectangle
is set related to the image size given in step 1).
3. SUBDEV_S_SELECTION with COMPOSE target on the SINK pad. The size of the
compose rectangle, if it differs from the size of the rectangle given in 2),
signifies user's wish to perform scaling.
4. SUBDEV_S_SELECTION with CROP target on the SOURCE pad. Configure cropping
performed by the subdev after scaling.
5. SUBDEV_S_SELECTION with COMPOSE target on the SOURCE pad. This configures
composition on the display if relevant for the subdevice. (In this case the
COMPOSE bounds will yield to the size of the display.)
6. SUBDEV_S_FMT on the SOURCE pad. The size of the image is defined by
setting CROP on the SOURCE pad, so SUBDEV_S_FMT only has an effect of
changing other parameters than size.
As defined in [2], when performing any of the configuration phases above,
the formats and selections are reset to defaults from each phase onwards.
For example, SUBDEV_S_SELECTION with CROP target on the SINK pad will
--- beyond its obvious function of setting CROP selection target on the SINK
pad --- reset the COMPOSE selection target on SINK pad, as well as the CROP
selection target and format on the SOURCE pad.
Definitions
===
/**
* struct v4l2_subdev_selection - selection info
*
* @which: either V4L2_SUBDEV_FORMAT_ACTIVE or V4L2_SUBDEV_FORMAT_TRY
* @pad: pad number, as reported by the media API
* @target: selection target, used to choose one of possible rectangles
* @flags: constraints flags
* @r: coordinates of selection window
* @reserved: for future use, rounds structure size to 64 bytes, set to zero
*
* Hardware may use multiple helper window to process a video stream.
* The structure is used to exchange this selection areas between
* an application and a driver.
*/
struct v4l2_subdev_selection {
__u32 which;
__u32 pad;
__u32 target;
__u32 flags;
struct v4l2_rect r;
__u32 reserved[8];
};
Both SUBDEV_S_SELECTION and SUBDEV_G_SELECTION would take struct
v4l2_subdev_selection as the IOCTL argument (RW).
The same target definitions and flags apply as in [1], with possible
exception of the PADDED targets --- see below. The flags will gain _SUBDEV
prefix after the existing V4L2 prefix.
Sample use cases
OMAP 3 ISP preview
--
The OMAP 3 ISP preview block provides cropping on preview sink pad, but also
horizontal averaging. The horizontal averaging may scale the image
horizontally by factor 1/n, where n is either 1, 2, 4 or 8.
The preview block also performs pixel format conversion from raw bayer to
YUV. Other image processing operations crops maximum of 12 columns and 8 rows
before the format conversion. After the format conversion, further 2 columns
are cropped.
To make this easy for the user, the driver assumes that all the features
affecting cropping are enabled at all times so the size stays constant for
the user.
This example only includes the preview subdev since it can be shown
independently. In the example, the preview subdev is configured to crop the
image by 100 pixels on all sides of the image. The horizontal averaging is
configured by factor 1/2, which translates 100 pixels from each side of the
original image. The preview sink pad format is 800x600 SGRBG10.
[crop] 0:preview:1 [crop (static), compose]
The initial state of the pipeline is:
preview:0 preview:1
compose (0,0)/788x592 (0,0)/788x592
crop(7,4)/788x592 (1,0)/786x592
fmt 800x600/SGRBG10 786x592/YUYV
This is due to hardware imposed cropping performed in the sink pad
as well as on the
