Hi all, Here is some more information about the Media Summit: Date: Monday September 12 Time: 8:45-18:00 Location: Convention Centre Dublin Room: The Liffey B - Part 1 (subject to change) Sponsored by: Cisco Systems Norway, Collabora and the Kodi Foundation We will have a projector or display to show presentations, power strips, a whiteboard and beverages. Lunch is sponsored by the Kodi Foundation, details to follow. It's co-located with the OSS Europe conference: https://events.linuxfoundation.org/open-source-summit-europe/ Attendees: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx> Nicolas Dufresne <nicolas@xxxxxxxxxxxx> Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx> Hidenori Kobayashi <hidenorik@xxxxxxxxxxxx> Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx> Jacopo Mondi <jacopo@xxxxxxxxxx> Michael Olbrich <m.olbrich@xxxxxxxxxxxxxx> Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> Ricardo Ribalda <ribalda@xxxxxxxxxxxx> Maxime Ripard <maxime@xxxxxxxxxx> Daniel Scally <djrscally@xxxxxxxxx> Jernej Škrabec <jernej.skrabec@xxxxxxxxx> Niklas Söderlund <niklas.soderlund@xxxxxxxxxxxx> (afternoon only) Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx> (from 11 am approx.) Michael Tretter <m.tretter@xxxxxxxxxxxxxx> Hans Verkuil <hverkuil@xxxxxxxxx> Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> Note: there are 2 seats left, so if you are interested in this, mail me. Tentative remote attendees: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> Benjamin MUGNIER <benjamin.mugnier@xxxxxxxxxxx> Regarding remote attendance: I plan to bring a second laptop with me and a good webcam. But whether this will work is not at all certain, esp. audio is often very poor. It very much depends on the room. More info to follow. The health and safety regulations will be those of the OSSE LF (updated on August 22): https://events.linuxfoundation.org/open-source-summit-europe/attend/health-and-safety/ As you can read above masks are needed for this event, so make sure you bring them! You also need to be fully vaccinated (Duh!), or show a negative test. See the details in the link. We also strongly recommend that you do a self-test before going to the Conference Centre for this meeting. Code of conduct: https://events.linuxfoundation.org/open-source-summit-europe/attend/code-of-conduct/ Based on the submitted topics I have made a first draft of the agenda. I have tried to keep the sensor-related topics to after 11:00 since Dave comes in later in the day. I am also making the (reasonable) assumption that most (if not all) attendees will be attending the ELCE/OSSE conference Tue-Fri as well. While it is nice if we can come to a conclusion in the time allotted for each topic, it's also OK if we can set up a small group that can discuss it further in the following days. If you raised a discussion topic, but will be in Dublin for only the Monday, then let me know. I added a guesstimate of the time needed for each topic. If you think that guesstimate is wildly off, then let me know. But remember: it's fine if we decide to discuss it further in the following days in a smaller group. If you present a topic, then please make a presentation. And if you have material you can share beforehand, then that would be great. We have the room from 8:30-18:00, so I moved a few things around since V1, in particular please come in a bit earlier so you can set everything up (power, internet, etc.) so we can begin at 9 AM sharp. Don't expect that the times below are precise (esp. after 11:00): past experience tells us that it can vary wildly. Draft Agenda V2: 8:40 Getting settled 9:00 Introduction 9:10 Hans: Presentation on CTA-861 & edid-decode 9:25 Nicolas: Stateless encoder progress 10:00 Ricardo: Introduce ChromeOS camera project 11:00 Break 11:15 Kieran: Fault tolerance I raised this in the past when we first started hitting the issue on Renesas platforms with multiple cameras in a single media graph, but now I think it's become more critical with desktop / laptop devices that are hitting the issue (i.e. the IPU3). Summary of issue: - Multiple cameras that can function independently successfully, are prevented from functioning or fully probing by V4L2 if one component of another camera fails to load or probe. If Camera A has a VCM, and Camera B does not, Camera B will not be available at all if Camera A's VCM is not fully probed, even though Camera B can be fully functional and complete. Even if Camera A does not have the VCM probed, it may still function successfully (with a fixed focal position) - but our current implementation will mean that it will not even be available to capture images. We talked about this quite a long time ago, and I believe the general consensus was that we can have events on the media graph. But unfortunately at the time, there was no development scheduled on that, and it wasn't something I was able to continue at the time. I'd like to bring it up to refresh the topic, and see if we can make some progress as it's now affecting more general devices. 11:45 Jacopo: Representing addition sensor processing stages. How to represent additional processing stages that happens on the sensor side, mostly additional subsampling/cropping that happen between the analogue cropping on the full pixel array and the final image sent on the wire. https://lore.kernel.org/linux-media/CAPY8ntA06L1Xsph79sv9t7MiDSNeSO2vADevuXZdXQdhWpSmow@xxxxxxxxxxxxxx/ Dave made a good introduction of the issue his email which got largely unanswered. The issue is particularly relevant for RAW sensors, where applying subsampling has an impact on the sensor's sensitivity and requires to adjust the gains and exposure accordingly. The V4L2 selection API falls short on this and the only other solution I am aware of is registering additional subdevices as the CCS driver does. 12:30 Lunch 13:30 Dave: On-sensor temperature reporting. Thread started by Benjamin at https://lore.kernel.org/linux-media/20220415111845.27130-3-benjamin.mugnier@xxxxxxxxxxx/ but no resolution over using hwmon API or V4L2 control. If hwmon then we need Media Controller framework to tie the sensor and thermal device together. It's recently been queried for IMX477 with the Pi (https://github.com/raspberrypi/libcamera/issues/19), but it will apply to many sensors. 13:50 Dave: Synchronising sensors for stereoscopic operation. How should that be configured? Allowing configuration from userspace would allow sensors to be operated independently which can be useful for test purposes, or should it be enforced from DT/ACPI? Do we set a default configuration for each sensor from DT/ACPI and then allow userspace to override should it wish? 14:10 Dave: Lens drivers. Each driver will have a "useful" range which is effectively dictated by the overall module. Should that be defined via DT as it is a feature of the platform, or leave the driver totally generic and expect userspace to do something sensible? In the case of simple systems without libcamera, do we set default for V4L2_CID_FOCUS_ABSOLUTE to a sensible hyperfocal distance, and can that again be defined in DT as it is defining the hardware? 14:30 Dave: Controlling sensor GPIO outputs. Controlling sensor GPIO outputs for things such as flash triggers, vsync, frame start/end, exposure start/end, etc. There is a huge range of features available so do we have any hope of standardising some of it, or do we end up hiding these away in the drivers with custom DT bindings to configure them? If we accept that there will be variation, can we vaguely standardise what those bindings look like? Or should these be V4L2 controls as things like pulse widths may want to be adjusted by userspace? 15:00 Break 15:30 Jacopo: Reconcile handling of regulator, gpios and clock on OF and ACPI platforms. We recently got a few series trying to reconcile handling of regulators, gpios and clocks on OF and ACPI platforms all of them doing the usual "similar but slightly different" thing: https://lore.kernel.org/linux-media/20220425061022.1569480-1-paul.elder@xxxxxxxxxxxxxxxx/ https://lore.kernel.org/linux-media/20220329090133.338073-1-jacopo@xxxxxxxxxx/ https://lore.kernel.org/linux-media/20220509143226.531117-1-foss+kernel@xxxxxxxxx/ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0c2c7a1e0d69221b9d489bfd8cf53262d6f82446 ACPI and OF handles clocks slightly differently, and it is not clear to me if ACPI based platform need explicit handling of clocks/regulator or ACPI does "the right thing" by itself (I'm afraid the answer is actually "it depends"). I'm ACPI illiterate so I cannot propose anything meaningful but if anyone is interested in discussing this further this might be a good time to do so ? 16:00 Laurent: V4L2 streams series. I'd like to discuss the V4L2 streams series, in particular how to upstream the parts that won't be upstream yet by mid-September. Discussing the next steps would also be useful, as there's lots we could build on top. 16:30 Laurent: How can we finalize conversion of v4l-utils to meson? 16:45-18:00 Anything else? Regards, Hans
