Re: [RFC PATCH v1 0/4] media: v4l2-subdev: Improve frame interval handling

Laurent Pinchart
2023-10-24T07:39:25Z

On Tue, Oct 24, 2023 at 10:31:57AM +0300, Tomi Valkeinen wrote:
> On 24/10/2023 03:51, Laurent Pinchart wrote:
> > Hello,
> >
> > This patch series improves frame interval handling in the V4L2 subdev
> > in-kernel and userspace APIs.
> >
> > Frame interval are exposed to userspace on pads and streams, but the
> > frame interval handling is currently implemented through a v4l2_subdev
> > video operation, without involving the subdev state. This makes frame
> > intervals a second class citizen compared to formats and selection
> > rectangles.
> >
> > Patch 1/4 starts by addressing the first issue, namely the frame
> > interval operations being video ops. This requires touching all the
> > drivers using frame intervals.
> >
> > Patch 2/4 then adds a 'which' field to the subdev frame interval
> > userspace API, allowing frame intervals to be tried the same way formats
> > and selection rectangles can. Again, the same drivers need to be touched
> > to preserve their current behaviour.
> >
> > Patch 3/4 adds support for storing the frame interval in the subdev
> > state, alongside the formats and selection rectangles, with similar
> > accessors and helper functions.
> >
> > Finally, patch 4/4 demonstrates how this is used in drivers, with the
> > thp7312 driver serving as an example. This driver isn't upstream yet,
> > the latest version can be found on the linux-media mailing list ([1]).
> >
> > Sakari, these patches conflict with your "[PATCH v3 0/8] Unify
> > sub-device state access functions" series. I plan to rebase on top once
> > it reaches the media tree. This shouldn't prevent reviewing this RFC in
> > the meantime :-)
>
> I think these look fine, but I'll do an official review when the non-RFC
> is posted.
>
> Should v4l2-compliance be updated?

Probably, although it's going to be difficult to test this feature,
especially given that none of the virtual drivers implement it.

> > [1] https://lore.kernel.org/linux-media/20231017132103.9914-1-laurent.pinchart@ideasonboard.com/
> >
> > Laurent Pinchart (4):
> > media: v4l2-subdev: Turn .[gs]_frame_interval into pad operations
> > media: v4l2-subdev: Add which field to struct
> > v4l2_subdev_frame_interval
> > media: v4l2-subdev: Store frame interval in subdev state
> > media: i2c: thp7312: Store frame interval in subdev state
> >
> > .../media/v4l/vidioc-subdev-g-client-cap.rst | 5 +
> > .../v4l/vidioc-subdev-g-frame-interval.rst | 17 +-
> > drivers/media/i2c/adv7180.c | 10 +-
> > drivers/media/i2c/et8ek8/et8ek8_driver.c | 12 +-
> > drivers/media/i2c/imx214.c | 12 +-
> > drivers/media/i2c/imx274.c | 54 +++----
> > drivers/media/i2c/max9286.c | 20 ++-
> > drivers/media/i2c/mt9m111.c | 20 ++-
> > drivers/media/i2c/mt9m114.c | 20 ++-
> > drivers/media/i2c/mt9v011.c | 24 +--
> > drivers/media/i2c/mt9v111.c | 22 ++-
> > drivers/media/i2c/ov2680.c | 10 +-
> > drivers/media/i2c/ov5640.c | 22 ++-
> > drivers/media/i2c/ov5648.c | 62 ++++----
> > drivers/media/i2c/ov5693.c | 10 +-
> > drivers/media/i2c/ov6650.c | 22 ++-
> > drivers/media/i2c/ov7251.c | 12 +-
> > drivers/media/i2c/ov7670.c | 22 +--
> > drivers/media/i2c/ov772x.c | 20 ++-
> > drivers/media/i2c/ov7740.c | 40 ++---
> > drivers/media/i2c/ov8865.c | 54 ++++---
> > drivers/media/i2c/ov9650.c | 20 ++-
> > drivers/media/i2c/s5c73m3/s5c73m3-core.c | 20 ++-
> > drivers/media/i2c/s5k5baf.c | 26 ++--
> > drivers/media/i2c/thp7312.c | 145 ++++++++++--------
> > drivers/media/i2c/tvp514x.c | 33 ++--
> > drivers/media/usb/em28xx/em28xx-video.c | 6 +-
> > drivers/media/v4l2-core/v4l2-common.c | 8 +-
> > drivers/media/v4l2-core/v4l2-subdev.c | 120 +++++++++++----
> > .../media/atomisp/i2c/atomisp-gc0310.c | 10 +-
> > .../media/atomisp/i2c/atomisp-gc2235.c | 10 +-
> > .../media/atomisp/i2c/atomisp-mt9m114.c | 10 +-
> > .../media/atomisp/i2c/atomisp-ov2722.c | 10 +-
> > .../staging/media/atomisp/pci/atomisp_cmd.c | 4 +-
> > .../staging/media/atomisp/pci/atomisp_ioctl.c | 4 +-
> > drivers/staging/media/imx/imx-ic-prp.c | 20 ++-
> > drivers/staging/media/imx/imx-ic-prpencvf.c | 20 ++-
> > drivers/staging/media/imx/imx-media-capture.c | 6 +-
> > drivers/staging/media/imx/imx-media-csi.c | 20 ++-
> > drivers/staging/media/imx/imx-media-vdic.c | 20 ++-
> > drivers/staging/media/tegra-video/csi.c | 12 +-
> > include/media/v4l2-common.h | 4 +-
> > include/media/v4l2-subdev.h | 79 ++++++++--
> > include/uapi/linux/v4l2-subdev.h | 13 +-
> > 44 files changed, 706 insertions(+), 404 deletions(-)