Shell & Display Next hackfest

Brno, 24-26 April inclusive

Primary contact: Carlos Soriano Sanchez <csoriano@redhat.com>
Secondary contact: Tomas Popela <tpopela@redhat.com>

Relevant GNOME team

Shell & mutter, possibly Design. Teams outside of GNOME will be key too, for KMS/DRM, Mesa, etc.

Description

Planning and development of the technical infrastructure for various features for display-next technologies, specifically those that need GNOME Shell to work in tandem with the GPU stack. One of the main examples of this is HDR support.

This hackfest intends to put together engineers across the display/GPU stack, including folks from freedesktop and the upstream kernel. It's a great opportunity for GNOMErs to meet and collaborate with members of other communities.

The proposed length of the hackfest is 2 full days and a third day for wrapping up during the morning and doing some local activity during the afternoon.

Agenda, goals

Goals The main goal is to plan the next 1-2 years of work and direction in how to support HDR, VRR and other new GPU and graphics technologies that are exposed to the final user through Mutter and Shell.

In addition, the second main goal is to discuss, plan and agree on how to improve KMS and Wayland APIs to better accommodate user space needs for these technologies, specially necessary for HDR.

The third main but optional goal is for the UXD team to discuss the next iteration of Shell designs, and expose their needs to the GPU, graphics and Shell/Mutter engineers to gather feedback on what's feasible and what APIs would be necessary.

Agenda

HDR - Leads: Jonas, Sebastian, Benjamin
- HDR modes (PQ, HLG, SBTM, and Metadata)
- Approaches for compositing SDR, color managed SDR and HDR
  - ICC workflow
  - Implicit color managed workflow
  - Gamut and tone mapping
  - Linear spaces for blending, scaling
- Viewing environment adjustment
  - Brightness/backlight adjustment
  - PQ absolute luminance TF
  - Tone mapping
- Mutter and GTK roadmap
- Wayland color-representation and color-management protocols
- HDR UX (Settings, enabling and disabling HDR, power considerations, etc)
- Dynamic Metadata support
VRR - Leads: Manasi, Michel
- State of the art
- Addressing apps bogging down Mutter
KMS properties – Leads: Sebastian, $ANYONE?
- More control over the connector
  - Min/Max BPC
  - YCC support and subsampling
  - Colorspace
  - Compression (DSC)
  - Broadcast RGB, Limited/Full range handling
- The KMS Color Pipeline
  - Continuing XDC HDR talk/workshop (Harry)
  - How to offload color transformations to the display controller
- Backlight control (Hans De Goede?)
- EDID/DisplayID/DDCCI
Direct scanout on non-compositing GPUs - Leads: Michel, Jonas
- NVIDIA Advanced Optimus equivalency
- Use cases and possible gains
- Missing pieces - KMS APIs, Mutter, driver support, etc.
- Coming up with a roadmap
UXD - Leads: AllanDay, JakubSteiner, TobiasBernard
- Optional, potential separate track to the rest of the event
- We have a number of shell design topics on the backlog, though whether we’ll be in a position to tackle these in the autumn is unclear

Code of Conduct

As for all GNOME-related events, the GNOME Events Code of Conduct and CodeOfConduct/PhotographyPolicy apply.

Any violations of either should be submitted to the event organizers (see above) or the GNOME Code of Conduct Committee

Timeline

1st day: attendees arrive
2nd day: plan work and do some work
3rd day: do more work
4th day: wrap up during the morning, sponsored activity (TBD) by Red Hat during the afternoon.

Possible Attendees

Name	Relevant contribution/aim	Arrives on	Departs on	Staying at	Confirmed attendance
Michel Daenzer	Red Hat - full GPU stack: drm/kms, VRR, Mesa				x
Niels de Graef	Red Hat - GPU team PO for HDR				x
Hans de Goede	Red Hat - Kernel client development			local	x
Sebastian Wick	Red Hat - HDR full stack developer
Jonas Adahl	Red Hat - Mutter maintainer
Carlos Soriano	Red Hat - logistics and Red Hat GPU team coordination	x	x	local	x
Allan Day	Red Hat - UXD
Benjamin Otte	Red Hat - GTK GL/color mgmt work with Sebastian, synchronizing client and compositor-side needs and technologies
Carlos Garnacho	Red Hat - Mutter maintainer
Florian Muellner	Red Hat - Shell maintainer
Robert Mader	Collabora - YUV support and firefox graphics related work
Alexander Goins	NVIDIA - HDR
Pekka Paalanen (pq)	Wayland/Weston maintainer, parts of CM&HDR protocol design and Weston implementation, color-and-hdr	x	x	Remote
Marco Trevisan	Canonical - Shell and Mutter contributor				x
Jesus Soto	Canonical
Melissa Wen	Igalia - KMS CRTC 3D LUT
Georges Basiel Stavracas Neto	Endless - Mutter/GNOME Shell maintainer
Sharma Shashank	AMD - HDR on Linux (Intel-display/I915 + Weston/Kodi)
Jiri Koten	Red Hat - Desktop PO
Harry Wentland	AMD - exposing per plane color
Tobias Bernard	Purism - UXD
Jakub Steiner	Red Hat - Pixel Pushing
Manasi Navare	Intel - leading kernel development of DSC and VRR at Intel

Additional possible key attendees (add your name in the table above for confirming interest in attendance and edit your relevant contribution)

Name	Relevant contribution/aim
Ville Syrjala	Intel kernel display developer
Daniel Vetter	Intel DRM maintainer
Dor Askayo	VRR contributor
Uma Shankar	Intel - exposing per plane color (cannot attend)
Simon Ser	SourceHut/Valve - Wayland/Mesa https://emersion.fr/about/
Hans-Kristian Arntzen	Valve - vkd3d-proton (pointed to Josh Ashton)
Pierre-Loup A. Griffais	Valve (pointed to Josh Ashton)
Josh Ashton	Valve - HDR on gamescope (cannot attend, possibly remotely)
David Edmudson	KDE - color/HDR
Vlad Zahorodnii	KDE
Xaver Hugl	KDE - VRR

Costs

One good option for accommodation close to the venue is: Hotel Vista - which is about €70 night.

Flights from EU around €200 to either Vienna or Prague. Then Student Agency train from any of those cities to Brno around €12.

How to get there

From Europe or faraway places

Fly to Vienna or Prague airport
Direct bus from the airport bus stations to Brno through https://www.studentagency.eu/en/. Reservation required in advance through that website.
Alternatively, train from those cities to Brno through https://www.studentagency.eu/en/ too.
- From Vienna airport, you will need to take a regular train to Vienna hbf (main train station a.k.a. hauptbahnhof). The regular train goes every 20 min aprox and tickets can be bought in the Vienna airport machines directly and takes around 30 min travel. Then you can take the Student Agency train to Brno from VIenna hbf.
- From Prague, you can take a bus to the main train station (a.k.a. Hlavni Nadrazi) through regular city buses in the Prague airport. A ticket can be bought in the yellow colored machines directly in the bus stations of the airport (Czech crown coins required I believe).

Venue

Red Hat offices, TPB-B. Hosted in the 1st floor, in the Plutonium and Selenium rooms.

You can get to the venue by tram number 12 from the center in "Ceska" tram stop as well as from the main train station "Hlavni Nadrazi", direction Technologicke Park. You can use the PubTram android and ios app to get times for the trams (every 7 min).

Accommodation and food

Food

QWERTY, Map - 5 min walking from the venue. Relatively small place with lighter Czech food.

Chilli Tree, Map - Reasonable quality and priced Thai food, including vegetarian and vegan options.

Forky's - Excellent modern vegan restaurant in the center. 20 min tram trip from the Venue.

Accomodation

One good option is: Hotel Vista - map - The best way to get to the venue from this hotel is taking bus number 65 in tram stop "Vozovna Medlánky" direction "Technologický park" and get out in the last stop, named "Technologický park", for a total of 7 min. Walking is about 15 min. - directions to the venue.

Previous discussions, organization threads, drafts, relevant links, etc

Note to organizers
it is expected that you have contacted relevant teams or groups for your hackfest prior to proposing it, for example if you plan to do an Art hackfest, contact the Art team for ideas.