Re: [PATCH 0/6] media: v4l2-isp: Add support for extensible statistics

From: Jacopo Mondi

Date: Wed Jun 03 2026 - 04:20:40 EST

Hi Antoine

On Mon, Jun 01, 2026 at 03:29:54PM +0200, Antoine Bouyer wrote:
> On 5/27/26 2:09 PM, Jacopo Mondi wrote:
> >
> >
> > Hi Sakari,
> >
> > On Fri, May 15, 2026 at 03:11:18PM +0200, Jacopo Mondi wrote:
> > > Hi Antoine, Keke
> > >
> > > On Wed, May 13, 2026 at 09:04:27AM +0800, Keke Li wrote:
> > > >
> > > > On 5/12/26 17:26, Antoine Bouyer wrote:
> > > > > [ EXTERNAL EMAIL ]
> > > > >
> > > > > Le 05/05/2026 à 18:49, Antoine Bouyer a écrit :
> > > > > > On 5/5/26 4:12 PM, Jacopo Mondi wrote:
> > > > > > >
> > > > > > >
> > > > > > > This series breaks out from Antonie's
> > > > > > > https://eur01.safelinks.protection.outlook.com/?
> > > > > > > url=https%3A%2F%2Fpatchwork.linuxtv.org%2Fproject%2Flinux-
> > > > > > > media%2Flist%2F%3Fseries%3D24043&data=05%7C02%7Cantoine.bouyer%40nxp.com%7Cd0e9f403856c4146996308deaab05cd1%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C639135871605732002%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=FXaz7QYQvS3s%2B4l9AFMrGgE7kmXlEil%2FKD6DibB0%2FJY%3D&reserved=0
> > > > > > >
> > > > > > > the extensible stats support and adds a few more patches on top to:
> > > > > > >
> > > > > > > - add support for per-block validation as suggested during the
> > > > > > > review of
> > > > > > > Ricardo's
> > > > > > > https://eur01.safelinks.protection.outlook.com/?
> > > > > > > url=https%3A%2F%2Fpatchwork.linuxtv.org%2Fproject%2Flinux-
> > > > > > > media%2Fpatch%2F20260504-smatch-7-1-v3-6-
> > > > > > > fda125c30058%40chromium.org%2F&data=05%7C02%7Cantoine.bouyer%40nxp.com%7Cd0e9f403856c4146996308deaab05cd1%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C639135871605751612%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=AiRH8MhIbXt3dr%2B2r3I6STE6TJAChylnH%2Fz3tLdS36k%3D&reserved=0
> > > > > > >
> > > > > > >
> > > > > > > - add two helper functions to v4l2-isp to ease handling of extensible
> > > > > > > statistics for drivers. An early user, based on a preliminary
> > > > > > > version
> > > > > > > of the patches is available here as a reference:
> > > > > > > https://eur01.safelinks.protection.outlook.com/?
> > > > > > > url=https%3A%2F%2Fpatchwork.linuxtv.org%2Fproject%2Flinux-
> > > > > > > media%2Flist%2F%3Fseries%3D24703&data=05%7C02%7Cantoine.bouyer%40nxp.com%7Cd0e9f403856c4146996308deaab05cd1%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C639135871605763086%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=%2Fpsb7Z3lb8ingDILxc3LoEWKTojl5BGMbk6FiR%2FcO9I%3D&reserved=0
> > > > > > >
> > > > > > >
> > > > > > > Antonie: I took the liberty to fold in your patches changes to address
> > > > > > > my comments on your v1. I pushed an un-squased version of the patches
> > > > > > > here:
> > > > > > > https://eur01.safelinks.protection.outlook.com/?
> > > > > > > url=https%3A%2F%2Fgitlab.freedesktop.org%2Flinux-
> > > > > > > media%2Fusers%2Fjmondi%2F-%2Ftree%2Fb4%2Fextensible-stats-
> > > > > > > unsquashed&data=05%7C02%7Cantoine.bouyer%40nxp.com%7Cd0e9f403856c4146996308deaab05cd1%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C639135871605775020%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=iF2BE0GZ8HcVPmOJDhbmLsXQDOXV9JvqfMK6DRPPvrg%3D&reserved=0
> > > > > > >
> > > > > > > so you can easily get the diff from this and your version. Please feel
> > > > > > > free to comment on these as you're the original author.
> > > > > >
> > > > > > Hi Jacopo
> > > > > >
> > > > > > Thanks for the rework and the links. I'm fine with your [SQUASH]
> > > > > > commits.
> > > > > >
> > > > > > If there are no other comments, I assume I can reuse the common patches
> > > > > > in my v2 then, and also apply the new helpers to neoisp driver changes.
> > > > > > They look very useful (especially to prevent out-of-bounds crashes I
> > > > > > observed when data_size was not set before filling stats :( ). I'll
> > > > > > check in your user example.
> > > > > >
> > > > > > BR
> > > > > > Antoine
> > > > >
> > > > > Hi Jacopo
> > > > >
> > > > > Do you think it would make sense to create a new generic V4L2_META_FMT
> > > > > too ? which can be used by all user of v4l2-isp extensible params a/o
> > > > > stats. To avoid each driver creating its own meta fmt with same purpose.
> > > > >
> > > > > Or do you think it could have side effects ?
> > > > >
> > > > > BR
> > > > > Antoine
> > > > >
> > > > > >
> > > > I think this proposal is excellent.
> > > > 🙂
> > >
> > > To me, platform-specific formats mostly serve for documenting the ISP blocks.
> > > In example
> > > https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/metafmt-rkisp1.html
> > >
> > > There might be ways to handle it without defining a dedicated format
> > > indeed.
> > >
> > > Sakari Laurent and Hans are in cc, what do they think ?
> > >
> >
> > We briefly discussed it on irc and a few days ago again.
> >
> > Am I correct you think this is a good idea ?
> >
> > Antonie, do you plan to include the two new generic formts in your new
> > version ? Should we have a single format for STATS and PARAMS too ? I
> > see merit in both ways, to be hones two formats sound better to me as
> > they apply to two different queue types (output for params and capture
> > for stats)
>
> Hi Jacopo
>
> I would personally prefer using a single format for both params and stats.
>
> In my view, the format describes how the meta buffer is structured (header,
> size, version, flags, etc.), and it should not depend on the queue type.
> Since both stats and params will use the exact same structure, then it makes
> sense to me to share a single format. Similar to how a pixel format applies
> to both source and sink queues.

You certainly have a point here!

>
> That said, if there is a consensus in favor of defining 2 separate formats,
> I am fine with following that direction.

Let's see if we can get feedback from Sakari/Hans/Laurent.
I'll re-ping them!

>
> For now, I don't plan to integrate the new generic format in my patch
> series. I would prefer to wait for converging on a solution (1 or 2 formats)
> first. Then, depending on timeline, yes I can integrate it.

If you want to re-send a new version out quickly feel free to use any
format. I hope we can sort this out quickly so you can rebase on
easily.

Thanks
j

>
> BR
> Antoine
>
> >
> > >
> > >
> > > > > > >
> > > > > > > Signed-off-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
> > > > > > > ---
> > > > > > > Antoine Bouyer (2):
> > > > > > > media: uapi: v4l2-isp: Add extensible statistics
> > > > > > > media: Documentation: uapi: Update V4L2 ISP for extensible stats
> > > > > > >
> > > > > > > Jacopo Mondi (4):
> > > > > > > media: v4l2-isp: Rename v4l2_isp_params_buffer_size
> > > > > > > media: v4l2-isp: Add per-block validation callback
> > > > > > > media: amlogic-c3: Implement per-block validation
> > > > > > > media: v4l2-isp: Add helpers for stats buffer
> > > > > > >
> > > > > > > Documentation/userspace-api/media/v4l/v4l2-isp.rst | 45 ++++++--
> > > > > > > .../media/platform/amlogic/c3/isp/c3-isp-params.c | 42 ++++++-
> > > > > > > .../media/platform/arm/mali-c55/mali-c55-params.c | 12 +-
> > > > > > > drivers/media/v4l2-core/v4l2-isp.c | 56 +++++++++
> > > > > > > include/media/v4l2-isp.h | 94 +++++++++++
> > > > > > > ++---
> > > > > > > include/uapi/linux/media/v4l2-isp.h | 125 +++++++++++
> > > > > > > ++--------
> > > > > > > 6 files changed, 294 insertions(+), 80 deletions(-)
> > > > > > > ---
> > > > > > > base-commit: d9c8c4adf23d17549c0ec9c85b99d85a0ee6cf18
> > > > > > > change-id: 20260504-extensible-stats-f2d6befcc1ce
> > > > > > >
> > > > > > > Best regards,
> > > > > > > --
> > > > > > > Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
> > > > > > >
> > > > > >
> > > > >
> > > >
>