ValveSoftware/gamescope

Make KMS "rotation" prop optional for non-libliftoff codepath

Open

#252 opened on Sep 3, 2021

View on GitHub
 (4 comments) (0 reactions) (0 assignees)C++ (355 forks)github user discovery
embeddedgood first issue

Repository metrics

Stars
 (4,809 stars)
PR merge metrics
 (PR metrics pending)

Description

Commit https://github.com/Plagman/gamescope/commit/8782dc2cd110ef169e7d5abf5e40c94763bf7a05 made the KMS "rotation" property mandatory. However some drivers don't support it: https://drmdb.emersion.fr/properties/4008636142/rotation

libliftoff can deal with this already: https://github.com/emersion/libliftoff/blob/bc0d0617acdd48e69272771237cad2684c07c901/plane.c#L245

However the "basic" codepath doesn't have this fallback.

  • If the "rotation" prop exists, set it.
  • If gamescope is rotated but the "rotation" prop doesn't exist, error out.
  • If gamescope is not rotated and the "rotation" prop doesn't exist, ignore.

Contributor guide

Research direction
Review the commit 8782dc2cd110ef169e7d5abf5e40c94763bf7a05 that made rotation mandatory. Examine the libliftoff fallback in plane.c line 245. Then implement similar conditional logic in the non libliftoff path: if rotation prop exists, set it; if gamescope is rotated and prop doesn't exist, error; else ignore.
Tech stack
cpp
Domain
computer graphics
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++Git
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65